India paper

The paper, Shared and Unique Components of Human Population Structure and Genome-Wide Signals of Positive Selection in South Asia, is free.

Summing up, our results confirm both ancestry and temporal complexity shaping the still on-going process of genetic structuring of South Asian populations. This intricacy cannot be readily explained by the putative recent influx of Indo-Aryans alone but suggests multiple gene flows to the South Asian gene pool, both from the west and east, over a much longer time span.

Dienekes: "I haven't read the paper fully yet (it's open access), but the abstract seems to agree with what I've written both here and over at the Dodecad blog, about South Asians being primarily a West Asian/South Asian variable mix." In fact, the authors note in the body of the paper:

Another example of an heuristic interpretation appears when we look at the two blue ancestry components (Figure 2B) that explain most of the genetic diversity observed in West Eurasian populations (at K = 8), we see that only the k4 dark blue component is present in India and northern Pakistani populations, whereas, in contrast, the k3 light blue component dominates in southern Pakistan and Iran. This patterning suggests additional complexity of gene flow between geographically adjacent populations because it would be difficult to explain the western ancestry component in Indian populations by simple and recent admixture from the Middle East.

Moreover:

Both PC2 and k5 light green at K = 8 extend from South Asia to Central Asia and the Caucasus (but not into eastern Europe). In an attempt to explore diversity gradients within this signal, we investigated the haplotypic diversity associated with the ancestry components revealed by ADMIXTURE. Our simulations show that one can detect differences in haplotype diversity for a migration event that occurred 500 generations ago, but chances to distinguish signals for older events will apparently decrease with increasing age because of recombination. In terms of human population history, our oldest simulated migration event occurred roughly 12,500 years ago and predates or coincides with the initial Neolithic expansion in the Near East. Knowing whether signals associated with the initial peopling of Eurasia fall within our detection limits requires additional extensive simulations, but our current results indicate that the often debated episode of South Asian prehistory, the putative Indo-Aryan migration 3,500 years ago (see e.g., Abdulla15) falls well within the limits of our haplotype-based approach. We found no regional diversity differences associated with k5 at K = 8. Thus, regardless of where this component was from (the Caucasus, Near East, Indus Valley, or Central Asia), its spread to other regions must have occurred well before our detection limits at 12,500 years. Accordingly, the introduction of k5 to South Asia cannot be explained by recent gene flow, such as the hypothetical Indo-Aryan migration.

First, note that the k5 "light green" ADMIXTURE component does in fact extend into and throughout Europe (apart from Sardinia). The authors believe they've shown "k5" must have "spread" well before the Neolithic. What they've actually demonstrated is that ADMIXTURE (at least as used here) will not be the tool to disentangle complex recent population movements in Eurasia.

23andMe sale Monday

For those who are interested.

"Huge" Genographic Project ancient DNA study underway?

A reader forwards a comment posted to a mailing list yesterday by a project administrator attending FamilyTreeDNA's Houston conference:

Report from the mixer -- Spencer Wells was there and spoke enticingly of a huge ancient DNA research project that's been underway for some time, in which, instead of a simple replacement by incoming Neolithic populations, they are seeing wave after wave of peoples coming over thousands of years, each wave adding a stratum superimposed on those before it. The set of haplogroups seen in the earlier strata were not like the ones we see today. In particular he says mtDNA H was not there until a fairly recent, post-Neolithic date.

It's clear from already-published ancient DNA results that at least some sublineages of H were present in Neolithic Europe -- but H does seem to have become much more common since then.

He is still apparently clinging to a rather old date for R1b, though. He seems to think it had a major expansion about 10,000 years ago. Haven't genetic genealogists mostly been arguing for a considerably more recent time frame? I hope to see some R1b experts engage him in dialog on that point.

That's a 20,000 year step in the right direction. I won't begrudge him the other 5,000 years for now. I just hope the "huge" ancient DNA effort underway includes Y chromosomes. Another comment from the FTDNA conference:

Katherine, Emily, Joan and Bonnie are already tweeting from the FTDNA conference. Their Twitter accounts are: @khborges, @Genealem, @Luxegen and @Greenleafy

You can also follow the hashtag #FTDNA2011 though not all the tweets are going out with the hashtag. [. . .]

FTDNA has tested over 600,000 people.

The Genographic Project has 450,000 public participation samples and 75,000 indigenous samples.

The Genographic Project has two Basque papers going into journals this week and another paper which includes mtDNA haplogroup U5 is due out next year.

And a few more twitter comments:

khborges Katherine H. Borges SW-Phase 1 of Geno is wrapping up. Phase 2 to begin #FTDNA2011

khborges Katherine H. Borges #FTDNA2011 #Genographic SW- 1 in 17 men in Med are descended from Phoenician traders

khborges Katherine H. Borges #FTDNA2011 #Genographic SW-East Asian human migration patterns follow the rivers

khborges Katherine H. Borges #FTDNA2011 #Genographic SW-10 papers are going off to the journals next week and about a dozen more in the pipeline

Luxegen Joan Miller SW - teaser - big announcement coming in Genographic project next year. #FTDNA2011

Jewish Liberalism: the Allinsmith Study

Polling data is not kind to Moldbug's hilarious explanation for Jewish leftism. In a 1940s survey of eight religious denominations, Congregationalist respondents were least liberal. In Boston, high-SES Jews were more likely to vote for Adlai Stevenson for president in 1952 than low-SES non-Jews -- and low-SES non-Jews voted for Stevenson at twice the rate of high-SES non-Jews.

The degree of commitment of American Jews to liberalism is different from the degree of that commitment among other religious groups. The difference is that the Jewish devotion to liberalism is not correlated with economic or educational status. This was demonstrated almost 20 years ago by Wesley and Beverly Allinsmith.2

Toward the close of World War II, the Allinsmiths asked 8,820 members of eight religious denominations whether they believed that the most important postwar task of the U.S. Government was to provide opportunity for people to get ahead on their own or "to guarantee every person a decent and steady job and standard of living."

Nationally, 47% of the people questioned preferred security to opportunity. As the percentage of manual workers in each denomination increased, the proportion favoring security rose. Status, education and income were inversely related to the choice of security. As one proceeded from Congregationalists to Presbyterians to Episcopalians to Methodists to Lutherans to Baptists and finally to Catholics, the preference for security steadily increased from 26% to 58%.

The Jews were the only exception to this rule. Although they were a very high status group ranking first in occupational level, third in educational level and fourth in economic level, 56% of them preferred security to opportunity. This was almost as high as the Catholic preference for security.

Moreover, within each of the eight religious denominations, the preference for opportunity was greatest among those with most education, highest status and best occupational level. Again, the Jews were the only exception.

The 1944 presidential vote also revealed this marked difference between Jewish and Gentile political behavior. The upper-class and upper-middle-class Christian denominations voted heavily against Roosevelt and in favor of Republican standard-bearer Thomas Dewey. Only 31.4% of the Congregationalists, 39.9% of the Presbyterians and 44.6% of the Episcopalians backed Franklin Delano Roosevelt. The more working-class denominations, however, voted heavily for him, particularly the Catholics who were 72.8% in his favor. In terms of their combined educational, occupational and status rank in the Allinsmith survey-that of second place-the Jews might well have been expected to vote Republican. Actually, they were 92.1% for Roosevelt. This overwhelming support was greater than that of any of the Christian denominations. [. . .]

However, in the 1952 elections, despite the fact that the Republican presidential candidate, Dwight D. Eisenhower, had led the Western coalition to victory over the Nazis, 75% of the Jewish voters supported Adlai E. Stevenson, a man who had played no role of any importance in World War II. There was no difference in the attitude of the candidates toward Jewry or the state of Israel. The issue was clearly one of moderation vs. liberalism. In a situation where American voters as a whole gave decisive support to Eisenhower, three-fourths of the Jews backed his Democratic opponent. Moreover, interviews in depth of Boston voters showed that only 30% of the Gentiles with high socioeconomic status, as against 60% of those with low socioeconomic status, backed Stevenson. Among Boston Jews, 72% of those with high status voted for Stevenson.

Source: Nathaniel Weyl's The Jew in American Politics, pp. 6-8

Penny starting to drop for academics

From "Ancient DNA suggests the leading role played by men in the Neolithic dissemination" (pdf):

The high frequency of G2a haplogroup in Neolithic specimens, whereas this haplogroup is very rare in current populations, also suggests that men could have played a particularly important role in the Neolithic dissemination that is no longer visible today. This would imply that intra-European migrations related to the metal ages may have strongly affected the modern gene pool.

I was intending to comment more, but for now I'll just mention:

(1) I agree with Jean M.: "MtDNA haplogroups were K1a (3), T2b (2), and one each of H3 and U5. Since it seems very likely that all of these except the U5 arrived in the Neolithic, I cannot agree with the conclusions of the authors that the spread of farming was male-led."

(2) The confirmed presence of E-V13 in Neolithic western Europe reinforces for me that those wanting to attribute the reported elevated levels of E-V13 in NE Wales to "Roman soldiers" or the like are probably mistaken.

Dental morphological evidence for European admixture in Mongolia and western China

Lee, C. and Scott, G. R. (2011), Brief communication: Two-rooted lower Canines—A European trait and sensitive indicator of admixture across Eurasia. American Journal of Physical Anthropology, 146: 481–485. doi: 10.1002/ajpa.21585

With the exception of Carabelli's trait, the European dentition is better known for the morphological traits that it does not exhibit rather than the ones that it does. One root trait, however, runs counter to the characterization of reduced and simplified European crowns and roots. Although a rare trait in general, two-rooted lower canines are much more common in Europeans than in any other regional grouping and, given adequate sample sizes, can be useful in evaluating gene flow between Europeans and neighboring groups. In European samples, two-rooted lower canines consistently exhibit frequencies of 5–8%. In our sample from northern Spain, the trait attains a frequency of almost 10%. In contrast, in Sub-Saharan Africans the trait is virtually unknown while in Asian and Asian-derived populations, it varies between 0.0 and 1.0%. Here we show that two-rooted canine frequencies for new migrants along the western frontiers of China and Mongolia ranged from 0–4%. These data suggest European-derived populations migrated into western China (Xinjiang Province) and Mongolia (Bayan Olgii Aimag) sometime during the late Bronze age (1000–400 BCE). [. . .]

One of the major concerns of Alexandersen (1963) regarding two-rooted lower canines revolved around the issue of ‘‘atavism.’’ This term, rarely used today, begs the question of whether or not this double rooted form was common at one time, then disappeared, only to reappear sometime later. Swindler (1995) notes that ‘‘the deciduous and permanent canines in the majority of living primates have a single root.’’ This suggests that two-rooted lower canines are not the ancestral condition in anthropoids or hominoids. Rather, the phenotype is a derived condition, found primarily in recent human populations distributed across Western Eurasia.

The presence of the two-rooted canines in East Asia may provide some clue as to the eastward migration of new populations into China and Mongolia. The largest numbers of individuals with this trait are concentrated along the western and northern frontiers of China and Mongolia. Archaeological excavations support the large scale movement of people into this area during the Bronze age (ca. 2200 BCE–400 BCE). Burial artifacts and settlement patterns suggest cultural and technological ties to the Afanasevo culture in Siberia, which in turn is linked archaeologically, linguistically, and genetically with the Indo-European Tocharian populations that appear to have migrated to the Tarim Basin ca. 4,000 years ago (Ma and Sun, 1992; Ma and Wang, 1992; Mallory and Mair, 2000; Romgard, 2008; Keyser et al., 2009; Li et al., 2010).

The appearance of a new population on the western frontier also supports the findings of previous research in cranial metrics, dental nonmetrics, and DNA. Using cranial metrics and archaeological dating, Han (1994) hypothesized the earliest large-scale migration into western China occurred during the early Bronze age (2000 BCE) from Central Asia or southern Siberia. Dental nonmetric data also support multiple migrations into western China (Xinjiang Province) from Central Asia during the Bronze age to Iron age (Lee, 2007; Zhang, 2010). mtDNA studies on archaeological and modern population samples from Xinjiang Province show heterogeneous Asian and European genetic signatures dating from the Bronze age to the present (Yao et al., 2004; Cui et al., 2010; Zhang et al., 2010; Li et al., 2010).

As the frequency of two-rooted canines is highest in European samples and low to nonexistent in Asians, we propose this trait was introduced into East Asia by Indo- European speaking groups or their affines crossing the western frontier of China and Mongolia. Further data are needed to clarify aspects of these population movements, including the identity of the migrants, along with the number, routes, and timing of the migrations.

Although two-rooted lower canines cannot offer the precision of DNA in evaluating the ancestry in individual skulls, this trait is a sensitive indicator of admixture wherever Europeans come in contact with Asian or African populations. As this distinctive trait can be scored with relative ease in large samples, it provides a useful supplemental tool in discerning gene flow between distantly related populations going back many millennia.

Daniel MacArthur twitter commentary from CSHL Personal Genomes meeting

This meeting took place a couple weeks ago -- dgmacarthur is presently posting from ICHG2011.

James Watson is asking a question. At least I think it's a question. #cshlpg
Yes, it was a question: hasn't ELSI just been a huge waste of money? Wait, no - he's back to talking again. #cshlpg

Manfred Kayser is talking about the genetics of human appearance, but his talk is untweetable. #cshlpg
Although Kayser's talk is untweetable it sounds as though a lot of this is close to publication - so stay tuned. #cshlpg

JV [Joris Veltman] discussing published analysis of de novo variants in mental retardation: http://bit.ly/olWpYK #cshlpg
JV: total number of de novo coding mutations is not higher in MR patients - but more likely to be in brain genes. #cshlpg

What fraction of the human genome is functional?

What fraction of the human genome is functional?

Chris P. Ponting1,3 and Ross C. Hardison2,3

Abstract

Many evolutionary studies over the past decade have estimated ?sel, the proportion of all nucleotides in the human genome that are subject to purifying selection because of their biological function. Most of these studies have estimated the nucleotide substitution rates from genome sequence alignments across many diverse mammals. Some ?sel estimates will be affected by the heterogeneity of substitution rates in neutral sequence across the genome. Most will also be inaccurate if change in the functional sequence repertoire occurs rapidly relative to the separation of lineages that are being compared. Evidence gathered from both evolutionary and experimental analyses now indicate that rates of “turnover” of functional, predominantly noncoding, sequence are, indeed, high. They are sufficiently high that an estimated 50% of mouse constrained noncoding sequence is predicted not to be shared with rat, a closely related rodent. The rapidity of turnover results in, at least, a twofold underestimate of ?sel by analyses that measure constraint across the eutherian phylogeny. Approaches that take account of turnover estimate that the steady-state value of ?sel lies between 10% and 15%. Experimental studies corroborate the predicted rates of loss and gain of noncoding functional sites. These studies show the limitations inherent in the use of deep sequence conservation for identifying functional sequence. Experimental investigations focusing on lineage-specific, noncoding, and functional sequence are now essential if we are to appreciate the complete functional repertoire of the human genome.

http://genome.cshlp.org/content/early/2011/09/30/gr.116814.110.abstract

More excerpts from Chris Stringer's "The Origin of Our Species"

I read this a few months ago, but never got around to posting anything on it.

On group selection:

However, more recently, biologists and anthropologists such as Paul Bingham and Samuel Bowles have returned to the issue by recruiting weaponry and genes to the cause of group selection. The argument goes that by joining together to use effective projectile weaponry, individual risks were reduced, and thus coalitions of warriors would have been advantageous for group defence and offence. Bingham proposed that this development would also have been important within societies by deterring free-riders who tried to reap the rewards of group membership without contributing their fair share of commitment to the associated costs or risks. However strong individually, they could soon be brought into line when faced with a coalition of spear-armed peers, who could act as general enforcers of within-group rules and solidarity. Bowles posited the idea that if Palaeolithic groups were relatively inbred and genetically distinct from each other, and warfare between groups was prevalent, then group selection via collaborative defence and attack could evolve and be maintained. Without warfare, a gene with a self-sacrificial cost of only 3 per cent would disappear in a few millennia, but with warfare, Bowles's model showed that even levels of self-sacrifice of up to 13 per cent could be sustained. He used archaeological data (although mainly post-Palaeolithic) to argue that lethal warfare was indeed widespread in prehistory, and that altruistic group-beneficial behaviours that damaged the survival chances of individuals but improved the group's chances of winning a conflict could emerge and even thrive by group selection. Moreover, the model could work whether the behaviour in question was genetically based or was a cultural trait such as a shared belief system. As mentioned above, Bowles's archaeological data do not come from the Palaeolithic, but there is one observation that does resonate with his views: the French archaeologist Nicolas Teyssandier has noted that the period of overlap of the last Neanderthals and first moderns in Europe was characterized by a profusion of different styles of stone points. This might reflect a sort of arms race to perfect the tips of spears, perhaps to hunt more efficiently, but equally, this could suggest heightened intergroup conflict.

On modern behavior:

In terms of innovation, we saw in chapter 1 that the apparently sudden florescence of the rich Upper Palaeolithic societies of Europe seduced many in the last century to consider that this period marked the real arrival of fully modern humans, even if areas like the Middle East or Africa had been rehearsal grounds for the revolution that was to be finally expressed in the caves of France. But as we have also seen, this Eurocentric viewpoint that the Cro-Magnons were the first "modern" people has been largely abandoned, although that is not to deny that something special did happen in the Upper Palaeolithic of Europe. If Africa was actually at the forefront of Palaeolithic innovations more than 40,000 years ago, why was that? As anthropologist Rob Foley has pointed out, the sheer size of Africa (one could easily fit China, India and Europe into its surface area), and its position straddling the tropics, certainly gave it advantages over any other area inhabited by early humans. The rapidity and repetition of climatic oscillations outside of Africa probably continually disrupted long-term adaptations by human populations in those regions. Thus Neanderthals in Europe and the descendants of Homo erectus in northern China were constantly faced with sudden range contractions and the extinction of large parts of their populations every time temperatures sank rapidly, as they often did. [. . .]

The complex climates of Africa may also explain why there seems to be no single centre of origin for the earliest signals of behavioural modernity. Perhaps North Africa (and the Middle East?) led the way 120,000 years ago, but as conditions deteriorated, populations there shrank back or even became extinct, as favoured environments rapidly vanished. Perhaps the torch of modernity was then kept alive further south at sites like Blombos and Klasies River Mouth, as conditions favoured that region for a while (give or take the interruption of events like the Toba eruption).Waves of population expansion and contraction could explain the brief but extensive florescence of the Still Bay culture with its rich symbolism, and the subsequent rise and fall of the Howieson's Poort with its innovative tiny hafted blades and engraved ostrich eggshells (recently described from Diepkloof rock shelter) more than 5,000 years later. And it is my guess (though we lack much data to support it) that East Africa became one of the next centres for behavioural evolution, about 60,000 years ago, as it was from there that modern humans (and their developing suite of modern behaviours) made their way out of Africa. [. . .]

The big picture is that we are predominantly of recent African origin, so is there a special reason for this? Overall, I think that the pre-eminence of Africa in the story of modern human origins was a question of its larger geographical and human population size, which gave greater opportunities for morphological and behavioural variations, and for innovations to develop and be conserved, rather than the result of a special evolutionary pathway. "Modernity" was not a package that had a unique African origin in one time, place and population, but was a composite whose elements appeared at different times and places, and were then gradually assembled to assume the form we recognize today.

On genetic evidence for archaic admixture:

Up to now, the big picture, from our autosomal, mitochondrial and Y-chromosome DNA, has generally lacked signs of introgression from other human species, although scientists such as John Relethford, Vinayak Eswaran, Henry Harpending and Alan Templeton have argued that indications were indeed there. Short branches in our gene trees, particularly in Y and mtDNA, have pointed to a simple, recent African origin, and simulations from mtDNA data of the level of possible Neanderthal and Cro-Magnon admixture had suggested that it was either zero or very close to zero. However, despite the fact that mtDNA and Y-DNA provide such clear genealogical signals, they constitute only about 1 per cent of our total DNA, and signs of hybridization were clearly lurking in the rest of our genome. [. . .]

A recent example of such work is the study by Jeffrey Wall and colleagues of 222 SNPs (see chapters 7 and 8) in the genes of people from West Africa (Yoruba), China and Europe. Many of the SNPs were tightly clustered, and so deviations from the expectation of them all sharing the same pattern of inheritance from a single recent African ancestral population should have shown up clearly. The majority met Out of Africa expectations, but analysis suggested that the populations did display unusual mutations in some genes, and these had different histories from each other, and when compared between the geographical samples. Wall argued that the most likely explanation was that there was not a single ancestral population for all the SNPs -- most fitted the bill, but some were apparently descended from ancestral groups that had been isolated from each other long enough to develop separate SNP mutational patterns, which had then been bequeathed in slightly different ways to the modern regional populations. Interestingly, although each showed a signal of some "archaic" (rather than recent African) genetic contribution, the strongest pattern was not in Europe (where the Neanderthals might have been the source), nor in China (where it might have come from Denisovans), but in West Africa -- a puzzling result. The work has been criticized because some of the anomalous genes might have developed via recent drift or strong selection, if the mutations were regionally advantageous, but enough have been found to convince sceptics like me that there probably was ancient admixture in Africa as well.

On Iwo Eleru:

West Africa, where the oldest known fossil, from the Iwo Eleru rock shelter in Nigeria, is thought to be less than 15,000 years old. This poorly preserved skeleton was excavated from basal sediments at Iwo Eleru in 1965 by archaeologist Thurstan Shaw and his team, and was associated with Later Stone Age tools. That latter fact alone would suggest a relatively young age, and a radiocarbon date on a piece of charcoal suggested an age of about 13,000 years. The skeleton, and particularly the skull and jaw, was studied in 1971 by Don Brothwell, my predecessor at the Natural History Museum, and he argued that while the specimen could be related to recent populations in West Africa, it actually looked rather different from them. I studied the skull for my Ph.D., with surprising results. I also found that it did not closely resemble recent African populations, but in its long and low shape it was actually closer to early moderns such as those from Skhul, and even to more primitive specimens such as Omo 2. This was decidedly odd for such a young skeleton, and so I recently collaborated in a new study of the specimen with archaeologist Philip Allsworth-Jones, dating expert Rainer Gruen and anthropologist Katerina Harvati. We first checked with Thurstan Shaw whether there were any hints that the skull could have been much older than previously suggested, and there were none. With the help of Nigerian archaeologist Philip Oyelaran, I obtained a fragment of bone from the skeleton and passed it to Gruen in order to check its age directly. His determination from a direct uranium-series age estimate is that the bone is unlikely to be older than 20,000 years, consistent with the stratigraphy, and associated archaeology and radiocarbon date. Finally, could Brothwell and I have been wrong about the unusual shape of the skull? Harvati used state-of-the-art geometric morphometric scanning techniques on an exact replica of the skull (which is now in Nigeria), and found, as we did, that it was quite distinct from recent African crania, and indeed from any modern specimen in her comparative sample. Her results placed the skull closest to late archaic African fossils such as Ngaloba, Jebel Irhoud and Omo 2 -- all thought to be at least 140,000 years old. So what does this mean? Because of the poor preservation of Pleistocene bones in West Africa, we have no other data on the physical form of the inhabitants of the region during the whole of the Pleistocene, so we have to be careful in interpreting an isolated specimen such as Iwo Eleru. But it does not seem to be diseased or distorted, and does indeed seem to indicate that Africa contained archaic-looking people in some areas when, and even long after, the first modern-looking humans had appeared. Support for this view comes from the work of anthropologist Isabelle Crevecoeur. Her restudy of the numerous Ishango fossils from the Congo has shown that these Later Stone Age humans were not only similar to Iwo Eleru in age, but also in the surprisingly archaic features found in their skulls, jaws and skeletons. [. . .]

Africa today has the greatest internal genetic variation of any inhabited continent, and its skull shapes show the highest variation. This is usually attributed to its greater size, larger ancient populations and deepest timelines for humanity. But could those timelines go back even further than we thought? Did the early modern morphology evolve gradually, and then spread outwards from a region like East Africa, completely replacing archaic forms within Africa, and then outside (as mtDNA data would suggest)? Or, could there have been a version of assimilation or multiregional evolution within Africa, with modern genes, morphology and behaviour coalescing from partly isolated populations across the continent? Given its huge size, complex climates and patchworks of environments, Africa could have secreted distinct human populations just as easily as the rest of the inhabited world. So was the origin of modern humans there characterized by long periods of fission and fusion between populations, rather than representing a sudden single event? And was the replacement of the preceding late archaic peoples not absolute, so that they were partly absorbed by the evolving moderns rather than completely dying out? In which case, did early Homo sapiens forms, and even the preceding species, Homo heidelbergensis, survive alongside descendant modern humans?

Possible reason we don't have pigmentation genes from Neanderthals:

If the interbreeding actually happened earlier, in a warmer region or a warmer period, maybe the Neanderthals involved were not light-skinned and cold-adapted European examples? In fact, the interbreeding might even have happened when people like those from Skhul-Qafzeh and Tabun were in the Middle East 120,000 years ago. If a thousand of those early moderns mixed with just fifty Neanderthals and then survived somewhere in Arabia or North Africa, could they have subsequently interbred with the Out of Africa emigrants 60,000 years later, and passed on their hidden component of Neanderthal genes?

Out of Eurasia

From Chris Stringer's most recent book ("The Origin of Our Species"):

And the evidence from Dmanisi is now being added to this rethink, since the lack of very ancient fossil human evidence from Asia, apart from Dmanisi, is considered by archaeologists like Robin Dennell and Wil Roebroeks to reflect a lack of preservation and discovery, rather than a real absence. Combining the primitiveness of the Dmanisi specimens and tools with a similar view of the Liang Bua finds, it is argued that there was a widespread phase of human evolution in Eurasia about 2 million years ago, which is now only represented by the isolated Dmanisi and "Hobbit" fossils. This alternative scenario has a small-brained and small-bodied pre-erectus species, perhaps comparable to Homo habilis or even a late australopithecine, dispersing from Africa with primitive tools over 2 million years ago, reaching the Far East and, eventually, Flores. In Asia, this ancestral species then gave rise to the Dmanisi people and Homo erectus, while Dmanisi-like people reentered Africa about 1.8 million years ago, and evolved into later populations there -- including, eventually, Homo sapiens. So the orthodoxy of Out of Africa 1 is being challenged because of new evidence, and new interpretations of old evidence.

Ancestry.com's "Human Genetic Diversity Project"

Ancestry.com will apparently be offering autosomal DNA testing soon. They just gave away 2000 free "upgrades" to people who had previously done Y or mtDNA tests through Ancestry DNA, evidently for a forthcoming service along the lines of 23andMe's Relative Finder.

What You'll Get
Your Genetic Ethnicity
By testing over 700,000 of your DNA markers, you'll see the mix of ethnicities you have in your genes and how they relate to your family tree.
More comprehensive DNA matching
Find more and closer relatives, overcome brick walls, confirm relationships and find common ancestors. Enhanced, simple web site tools

The consent form contains some additional details, which I haven't seen discussed elsewhere:

1. What is the research project?

The Ancestry DNA's Human Genetic Diversity Project ("The Project") will collect, preserve and analyze genetic information, genealogical pedigrees, historical records, surveys, and other information (collectively, "Information") from people all around the world in order to better understand human evolution and migration, population genetics, ethnographic diversity and boundaries, genealogy, and the history of our species. Researchers hope that the Project will be an invaluable genealogic tool for future generations and will engage the interest of a wide range of scholars interested in genealogy, anthropology, evolution, languages, cultures, medicine, and other topics. The Information will not be used for medical purposes in the treatment or diagnosis of any individuals. [. . .]

2. What information will be collected?

The Project will collect genetic, genealogical and health information that has been stripped of any personally identifiable information in order to study the history of our species. Genes are in your cells, and they are what make you different from anyone else. Some genes control things like the color of your hair or eyes. Genetic information includes your genotype that is discovered when Ancestry DNA processes your saliva or is otherwise provided by you to Ancestry DNA (the "Genetic Information") when you choose to use the Ancestry DNA service. Genealogical information is your pedigree, ethnicity, family history, and other information about you that is either provided by you or is gleaned from publicly available documents on Ancestry.com's website and other locations (the "Genealogical Information"). Health information includes self-reported information from you such as medical conditions, diseases, other health-related information, personal traits, and other information that is either provided by you or is gleaned from publicly available documents on Ancestry.com's website and other locations (the "Health Information").

In all cases for this Project, personally identifiable information about specific study participants (such as name and birth date) is removed from the Information before it is compiled as part of this Project.

The Project will take all of this information (that is already stripped of personally identifiable information) and compile it into a single data summary to minimize the possibility that any individual participant can be identified by any researcher or other individual from the Information.

3. How will the information be used?

Your Information will be combined with others and used to further the Project's objectives of increasing our understanding the components that define the history of our species. Discoveries made as a result of this research could be used in the study of genealogy, anthropology, evolution, languages, cultures, medicine, and other topics.

Previously, ancestry.com have advertised for a PhD population geneticist:

The right person will be using a huge dataset of information from all over the world, developing methods and experimental design to improve results in genotyping data to inform pedigrees. This is not (yet) for medical research and, as such, is not regulated by the FDA. [ . . .] We are mounting a major effort to use genomics to shed light on human diversity, origins and relatedness. The successful candidate will join our efforts to develop and apply analysis pipelines to exploit genotyping data in order to provide information about countries of origin, relatedness and apply genetic information to the construction of human pedigrees. In this position, you will develop, implement and improve methods to use SNP data to provide information on relatedness and genetic origins of humans. You will work closely with other biologists in analyzing data as well as with members of the product development team. This position offers an exciting opportunity to apply cutting edge computational approaches to an unprecedented, large-scale set of pedigreed human genome data. Characteristic duties will include: • Develop, benchmark and implement data analysis pipelines for SNP genotyping data • Evaluate significance of results and recommend changes in experimental design to improve results • Develop, benchmark and implement methods to use genotyping data to inform pedigrees. • Identify new experimental and/or analytic approaches that will improve the outcome of the study • Manage collaborations with laboratory and informatics staff • Successfully communicate scientific concepts to a diverse community of scientists and laypeople Key Responsibilities / Performance Requirements: • Doctorate degree in statistical genetics, population genetics, statistics or a related field. • Candidates should have a track record of productive research in statistical and population genetics • Experience in human population genetics and genotyping • Ability to manipulate large data sets • Programming skills in UNIX/LINUX operating systems, and fluency in standard genetic analytic software (such as R/Bioconductor, EIGENSOFT, MACH, PLINK, ADMIXMAP) • Experience in molecular biology and high-throughput environments would be a significant advantage. • Excellent organizational skills • Superior oral and written English communication skills required. • Must be able to manage multiple simultaneous long-term projects while meeting frequent project deadlines in a fast-paced environment. • Must be able to translate high-level biological questions into concrete tasks.

Denisovans: Homo erectus after all?

Greg Cochran:

The new paper in Science about an Australian genome (An Aboriginal Australian Genome Reveals Separate Human Dispersals into Asia) hints at something new. Comments in the supplement (and by Ann Gibbon) suggest that the Denisovans may stem from Homo erectus, at least in part, rather than being a sister group to Neanderthals as suggested in the paper by Reich and Patterson back in December. In the supplement, the authors suggest that they may be a sister clade to the last common ancestor of Neanderthals and modern humans. Ann Gibbons say the same, concerning the Denisovan girl whose pinky we found: “She was not a modern human, but a descendant of Homo erectus, an ancestral species that left Africa almost 2 million years ago. “

Denisovan mtDNA is deeply diverged from modern human or Neanderthal mtDNA, while the Denisovan teeth found look strangely old-fashioned. Moreover, it now looks as if admixture between hominid subspecies is the norm rather than the exception. So, although Denisovans as an admixture between H. erectus and some branch of Neanderthals was always a possibility, evidence, signs, and portents are starting to make it look likely.

From the supplementary data (pdf) for the Aborigine genome paper:

Denisovans are more elusive. The term refers to a hypothetical population or possible species of archaic hominin, identified on the basis of ancient DNA, and with possible genetic affinities to both H. erectus and H. sapiens/neanderthalensis. They have been proposed as a sister clade to the last common ancestor of Neanderthals and modern humans.

"East Asian" mtDNA in Neolithic Hungary?

I don't have access to the paper at the moment. According to Jean M:

The details have been added to Ancient Western Eurasian DNA. The team actually tested remains from:

• Earliest Neolithic in Hungary, the Körös (N9a, C5, H? and a novel haplogroup 16235G, 16261T, 16291T, 16293G, 16304C)
• Alföld (N1a, N9a, D1/G1a1, H?. The reported M/R24 is a partial result)
• Final Neolithic Lengyel culture (H?)
• 9th-century AD Zalavár (H?)
• 16th-century AD Dobóruszka (U3)
• 19th-century mummies from Vác Dominician Church (H?, H12, N9a. Another mummy was tested, but produced different results for teeth and bone, presumably from contamination. I have not reported these results therefore)

Definitely interesting, but as John Hawks notes: "we need not maintain that the haplogroups presently common in East Asia have necessarily been there all that long."

Ötzi's Y-DNA haplogroup: G2a4

A few days ago a commenter at Dienekes' posted that this information had been revealed by "Dr. Eduard Egarter-Vigl, Head of Conservation and Assistant to research projects of the Archaeological Museum in Bozen [. . .] in a documentary [Ötzi, ein Archäologie-Krimi] broadcast by 3sat on 10th august 2011." Now someone has uploaded the relevant clip:

Subtitles: "Since six months, the full decoding of the genome of the Iceman is done. [. . .] Certain genes that are relevant to the origin, Y-chromosome, for example, can be examined well. [. . .] And the haplogroup to which the Iceman belonged is the haplogroup G2a4. [. . .] And this group is known, that it is now very rare in Europe. Interestingly, it is still in Sardinia. Sardinia is as an island a so-called micro-isolate where the poulation has hardly changed and so has developed genetically fairly constant. But there is this haplogroup in Eurasian regions, ie those from which we know that Europe was actually populated."

Sample size equals one, but the presence of G2a and absence of R1b is consistent with previous ancient DNA findings for Neolithic western and central Europe.

Haplogroup C mtDNA in Caucasoids does not necessarily indicate "Mongoloid" admixture

Dienekes writes:

Jean M links to a Master's thesis, which discovered the following:

While most of our samples possessed mtDNA haplotypes that can be linked to European and Near Eastern populations, three Neolithic and all three Bronze Age individuals belonged to mtDNA haplogroup C, which is common in East Eurasian, particularly South Siberian, populations but exceedingly rare in Europe. Phylogeographic network analysis revealed that our samples are located at or near the ancestral node for haplogroup C and that derived lineages branching from the Neolithic samples were present in Bronze Age Kurgans. In light of the numerous examples of mtDNA admixture that can be found in both Europe and Siberia, it appears that the NPR and South Siberia are located at opposite ends of a genetic continuum established at some point prior to the Neolithic. This migration corridor may have been established during the Last Glacial Maximum due to extensive glaciation in northern Eurasia and a consequent aridization of western Asia. This implies the demographic history for the European gene pool is more complex than previously considered and also has significant implications regarding the origin of Kurgan populations.

[. . .] The Dnieper-Donets population was described as robust Europeoid by Soviet anthropologists as was the Andronovo/Afanasevo tradition further east. It is interesting that Mongoloid admixture has been detected in both groups. I would not have guessed that this would have extended that far west and south. It seems that M. G. Levin may have been right when he stated that the Mongoloid elements penetrated far into eastern Europe.

I see no reason to believe the presence of haplogroup C indicates a "Mongoloid component". Stephen Oppenheimer sees C/Z mtDNA entering Mongoloids as part of an "intrusive" element "likely to have arrived from farther west in Asia, along with the eastern spread of the Upper Palaeolithic technology that appeared in Kara Bom in the Russian Altai 43,000 years ago." If this is correct, the presence of C in robust steppe Caucasoids would not be surprising. Oppenheimer has C/Z originating in western South Asia and entering Central Asia "round the western end of the Himalayas" 40-50,000 years ago, whereas Mongoloids (and "real" East Eurasian haplogroups) ultimately originate in SE Asia. Rather than indicating Mongoloid admixture "penetrated far into Eastern Europe", the presence of C mtDNA this early and this far west means one can't simply write off C and Z lineages in more easterly ancient Caucasoids (like some of those those buried at Xiaohe) -- or in Icelanders, for that matter -- as the product of Mongoloid admixture.

From Oppenheimer's Out of Eden:

Sex Chromosome Evolution and Medicine

A talk from earlier this year by David Page. Slides available here (pdf).

Contra the view promoted by Bryan Sykes, the Y chromosome is not dying.

Greater policing required to enforce cooperation in "diverse" societies

A Test of Evolutionary Policing Theory with Data from Human Societies (PLoS ONE):

In social groups where relatedness among interacting individuals is low, cooperation can often only be maintained through mechanisms that repress competition among group members. Repression-of-competition mechanisms, such as policing and punishment, seem to be of particular importance in human societies, where cooperative interactions often occur among unrelated individuals. In line with this view, economic games have shown that the ability to punish defectors enforces cooperation among humans. Here, I examine a real-world example of a repression-of-competition system, the police institutions common to modern human societies. Specifically, I test evolutionary policing theory by comparing data on policing effort, per capita crime rate, and similarity (used as a proxy for genetic relatedness) among citizens across the 26 cantons of Switzerland. This comparison revealed full support for all three predictions of evolutionary policing theory. First, when controlling for policing efforts, crime rate correlated negatively with the similarity among citizens. This is in line with the prediction that high similarity results in higher levels of cooperative self-restraint (i.e. lower crime rates) because it aligns the interests of individuals. Second, policing effort correlated negatively with the similarity among citizens, supporting the prediction that more policing is required to enforce cooperation in low-similarity societies, where individuals' interests diverge most. Third, increased policing efforts were associated with reductions in crime rates, indicating that policing indeed enforces cooperation. These analyses strongly indicate that humans respond to cues of their social environment and adjust cheating and policing behaviour as predicted by evolutionary policing theory.

Svante Paabo TED talk on Neanderthal admixture

Posting without having watching watched it yet.

"Sharing the results of a massive, worldwide study, geneticist Svante Pääbo shows the DNA proof that early humans mated with Neanderthals after we moved out of Africa. (Yes, many of us have Neanderthal DNA.) He also shows how a tiny bone from a baby finger was enough to identify a whole new humanoid species."

Next PoBI paper should be more interesting

Another ICHG/ASHG 2011 abstract:

People of the British Isles: An analysis of fine-scale population structure in a UK control population. S. Leslie1, B. Winney1, G. Hellenthal2, S. Myers2, A. Boumertit1, T. Day1, K. Hutnik1, E. Royrvik1, D. Lawson3, D. Falush4, P. Donnelly2, W. Bodmer1 1) Department of Oncology, University of Oxford, Oxford, United Kingdom; 2) Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom; 3) Department of Mathematics, University of Bristol, Bristol, United Kingdom; 4) Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.

There is a great deal of interest in fine scale population structure in the UK, both as a signature of historical immigration events and because of the effect population structure may have on disease association studies. Although population structure appears to have a minor impact on the current generation of genome-wide association studies, it is likely to play a significant part in the next generation of studies designed to search for rare variants. A powerful means of detecting such structure is to control and document carefully the provenance of the samples involved. Here we describe the collection of a cohort of rural UK samples (The People of the British Isles), aimed at providing a well-characterised UK control population that can be used as a resource by the research community as well as providing fine scale genetic information on the British population. So far, some 4000 samples have been collected, the majority of which fit the criteria of coming from a rural area and having all four grandparents from approximately the same area. Three thousand samples were genotyped on the Illumina 1.2M and Affymetrix v6.0 platforms as part of WTCCC2. Using a novel clustering algorithm that takes into account linkage disequilibrium structure, approximately 3000 of the samples were clustered, using these comprehensive genotyping data, into more than 50 groups purely as a function of their genetic similarities without any reference to their know locations. When the appropriate geographical position of each individual within a cluster is plotted on a map of the UK, there is a striking association between clusters and geography, which reflects to a major extent the known history of the British peoples. Thus, for example, even individuals from Cornwall and Devon, the two adjacent counties in the southwestern tip of Britain, fall into different, but coherent clusters. Further details of this comprehensive analysis of the genetic structure of the People of the British Isles, together with a description of the provenance of the samples, will be give in the presentation. We believe that this is the first time that such a detailed fine scale genetic structure of a population of generally very similar individuals has been possible. This has been achieved through, on the one hand, a careful geographically structured collection of samples and, on the other hand, an approach to analysis that takes into account fully the linkage disequilibrium structure of the population.

An estimate of black admixture in white Americans

An ICHG/ASHG 2011 abstract (below) reports some results from a study of the 23andMe database. I see various potential issues with the research as described in the abstract; but while the numbers are not definitive, these estimates are likely to be by far the most accurate to date. What's clear is the overwhelmingly huge majority of white Americans have zero black ancestry. All previous sensible analyses of genetic data agree, and any other result would be difficult to reconcile with American history -- however disappointing that might be to "Multiracial Voice"-types and race denialists.

In 2002, Mark Shriver claimed 30% of white Americans have on average about 2% African ancestry, the average for the population as a whole coming out to about 0.7%. Shortly thereafter, in a different interview, Shriver lowered his estimate, purporting "about 10 percent of [the European-American population] have some African ancestry". Subsequently, another principal of DNAprint revised the estimate still further downward: "Five percent of European Americans exhibit some detectable level of African ancestry". That too was an overestimate. 23andMe, examining the genomes of vastly larger numbers of people using thousands of times as many SNPs, estimates "about 2%" of "European Americans" have any detectable autosomal black ancestry. And three quarters of that 2% have only "about 0.5%" African ancestry (i.e., less than Shriver in 2002 claimed the average American carried).

Exceptions to the "One Drop Rule"? DNA evidence of African ancestry in European Americans. J. L. Mountain1, J. M. Macpherson1, C. B. Do1, B. T. Naughton1, R. A. Kittles2, N. Eriksson1 1) 23andMe, Inc, Mountain View, CA; 2) Institute of Human Genetics, University of Illinois at Chicago, Chicago, IL.

Genetic studies have revealed that most African Americans trace the majority (75-80%, on average) of their ancestry to western Africa. Most of the remaining ancestry traces to Europe, and paternal lines trace to Europe more often than maternal lines. This genetic pattern is consistent with the "One Drop Rule,” a social history wherein children born with at least one ancestor of African descent were considered Black in the United States. The question of how many European Americans have DNA evidence of African ancestry has been studied far less. We examined genetic ancestry for over 77,000 customers of 23andMe who had consented to participate in research. Most live in the United States. A subset of about 60,000 shows genetic evidence of fewer than one in 16 great-great-grandparents tracing ancestry to a continental region other than Europe. They are likely to consider themselves to be entirely of European descent. We conducted two analyses to understand what fraction of this group has genetic evidence of some ancestry tracing recently to Africa. We first identified individuals whose autosomal DNA indicates that they are predominantly of European ancestry, but who carry either a mitochondrial (mt) DNA or Y chromosome haplogroup that is highly likely to have originated in sub-Saharan Africa. Of the 60,000 individuals with 95% or greater European ancestry, close to 1% carry an mtDNA haplogroup indicating African ancestry. Of approximately 33,000 males, about one in 300 trace their paternal line to Africa. We then identified the subset of these European Americans who have estimates of between 0.5% and 5.0% of ancestry tracing to Africa. This subset constitutes about 2% of this set of individuals likely to be aware only of their European ancestry. The majority (75%) of that group has a very small estimated fraction of African ancestry (about 0.5%), likely to reflect African ancestry over seven generations (about 200 years) ago. We estimate that, overall, at least 2-3% of individuals with predominantly European ancestry have genetic patterns suggesting relatively deep ancestry tracing to Africa. This fraction is far lower than the genetic estimates of European ancestry of African Americans, consistent with the social history of the United States, but reveals that a small percentage of “mixed race” individuals were integrating into the European American community (passing for White) over 200 years ago, during the era of slavery in the United States.

Was there ever a Ruling Class? 1000 years of Social Mobility

According to Gregory Clark, because of regression to the mean and the lack of any (e.g., racial) barrier preventing gene flow across classes, there was never a persistent ruling class in England.

Notes from a presentation by Clark last year containing "work in progress from a planned book on social mobility over the long run" (pdf):

What is the fundamental nature of human society? Is it stratified into enduring layers of privilege and want, with some mobility between the layers, but permanent social classes? Or is there, over generations, complete mobility between all ranks in the social hierarchy, and complete long run equal opportunity? [. . .]

This book systematically exploits a new method of tracing social mobility over many generations, surnames, to measure the persistence of classes over as much as 800 years, 24 generations. It looks at societies where surnames are inherited, unchanged, by children from fathers. In such cases they thus serve as a tracer of the distant social origins of the modern population (and interestingly also as a tracer of the Y chromosome).

In this role surnames are a surprisingly powerful instrument for measuring long run social mobility. The results they reveal are clear, powerful, and a shock to our casual intuitions.

(1) In England, where we can trace social mobility back to 1066 using surnames, there were never any long persistent ruling and lower classes for the indigenous population: not in medieval England, and not now. About 5-6 generations were, and are, enough to erase most echoes of initial advantage or want. For the English class is, and always was, an illusion. Histories such as those of the Stanley family turn out to be rare exceptions, not the rule.

(2) Paradoxically, while England reveals complete long run mobility, the rates of social mobility per generation, better measured by looking over multiple generations, turn out to be lower than is conventionally estimated. But the mathematics of mobility is such that even such slow regression to the mean, over time, will completely erase initial advantage and want.

(3) The rate of social mobility in England was as high in the middle ages as it is now. The arrival of the whole apparatus of free public education in the late nineteenth century, and the elimination of nepotism in government and private firms, has not improved the rate of social mobility.

(4) The extraordinarily complete long run mobility of England is likely typical of other western European societies. But other countries, in contrast, do exhibit persistent social classes over hundreds of years. In the US, for example, the Black population has persisted at the bottom of the social order, and the Jewish population at the top. In Chile surname evidence shows the indigenous population has remained at the bottom since the Spanish conquest of 1541. [. . .]

(7) Though parents at the top of the economic ladder in any generation in preindustrial England did not derive any lasting advantage for their progeny, there was one odd effect. Surname frequencies show was that there was a permanent increase in the share of the DNA in England from rich parents before 1850. After 1850 a frequency effect operated, but in reverse. Surname frequencies show the DNA share of families in England who were rich in 1850 declined relative to that of poor families of the same generation by 2010. [. . .]

What is the meaning and explanation of these results? This is a much more contentious and difficult area. The book argues for the following conclusions:

A. Why can’t the ruling class in a place like England defend itself against downwards mobility? If the main determinants of economic and social success were wealth, education and connections then there would be no explanation of the consistent tendency of the rich to regress to the society mean. Only if genetics is the main element in determining economic success, if nature trumps nurture, is there a built-in mechanism that ensures the observed regression. That mechanism is the intermarriage of the rich with those from the lower classes. Even though there is strong assortative mating, since this is based on the phenotype created in part by chance and luck, those of higher than average innate talent tend to systematically mate with those of lesser ability and regress to the mean.

B. Racial, ethnic and religious differences allow long persisting social stratification through the barriers they create to this intermarriage. Thus for a society to achieve complete social mobility it must achieve cultural homogeneity. Multiculturalism is the enemy of long run equality.

On the Normans:

Another R1b paper

The peopling of Europe and the cautionary tale of Y chromosome lineage R-M269 (full text freely accessible):

Recently, the debate on the origins of the major European Y chromosome haplogroup R1b1b2-M269 has reignited, and opinion has moved away from Palaeolithic origins to the notion of a younger Neolithic spread of these chromosomes from the Near East. Here, we address this debate by investigating frequency patterns and diversity in the largest collection of R1b1b2-M269 chromosomes yet assembled. Our analysis reveals no geographical trends in diversity, in contradiction to expectation under the Neolithic hypothesis, and suggests an alternative explanation for the apparent cline in diversity recently described. We further investigate the young, STR-based time to the most recent common ancestor estimates proposed so far for R-M269-related lineages and find evidence for an appreciable effect of microsatellite choice on age estimates. As a consequence, the existing data and tools are insufficient to make credible estimates for the age of this haplogroup, and conclusions about the timing of its origin and dispersal should be viewed with a large degree of caution.

I find it hard to get too excited about this paper. As discussed previously, amateurs looking at more finely-resolved subclades using larger numbers of STRs do find trends in diversity that seem to point to an E. European origin for W. European R1b. I expect we'll have to wait a couple years, for overwhelming evidence to accumulate in the form of ancient DNA results and SNP-based dating, before seeing the correct route and timing of the entry of R1b into Europe widely agreed upon by academics. BBC article:

The extent to which modern Europeans are descended from these early farmers versus the indigenous hunter-gatherers who settled the continent thousands of years previously is a matter of heated debate. [. . .]

More than 100 million European men carry a type called R-M269, so identifying when this genetic group spread out is vital to understanding the peopling of Europe. [. . .]

A more recent origin for R-M269 than the Neolithic is also possible. But researchers point out that after the advent of agriculture, populations in Europe exploded, meaning that it would have been more difficult for incoming migrants to displace local people.

From the paper:

If the R-M269 lineage is more recent in origin than the Neolithic expansion, then its current distribution would have to be the result of major population movements occurring since that origin. For this haplogroup to be so ubiquitous, the population carrying R-S127 would have displaced most of the populations present in western Europe after the Neolithic agricultural transition.

Although the debate is commonly framed as Paleolithic vs. Neolithic, many lines of evidence suggest the correct answer is the third option: major post-Neolithic population movement.

Adaptive introgression of Denisovan HLA alleles across Asia?

John Hawks:

If it turns out that we have widespread adaptive introgression in Asia today from Denisovans, that will change the game of studying the origins of these populations. Based on the genome-wide comparison, it looks like the genetic interaction that led to the habitation of Asia did not involve Denisovans, who contributed only to populations at the most eastern extreme of habitation in island Southeast Asia. But the only Denisovans we know about lived near the geographic center of the Asian landmass, not at the extreme southeastern extreme.

The HLA pattern may suggest a more widespread pattern of mixture across Asia, which was later overwritten by population movements of people who didn't have Denisovan ancestry. That means that the habitation of Asia was a process of successive migrations and replacements, which imperfectly covered up the evidence of archaic intermixture. The genes that remain as signs of this intermixture are those that had selective advantages in later populations.

The paper: The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans

Deary / Visscher IQ paper

Those who read Sailer learned of this study a couple weeks ago. I've finally gotten around to looking at the actual paper, which seems convincing enough to me in doing what it says it does -- demonstrating "human intelligence is highly heritable and polygenic".

TGGP draws attention to comments by a blogger (Kevin Mitchell) who claims the paper "failed to establish the polygenic nature of the trait", but I don't see that Mitchell has a case. Mitchell:

I would interpret these findings very differently. What the authors do is analyse GWAS data in a very unusual way – they are not interested in finding specific SNPs affecting the trait, they simply use the SNPs to measure genetic relatedness between individuals.

As Mitchell then acknowledges, the paper does include a standard GWAS, the results of which are negative: at the level of individual SNPs not a single "replicable genome-wide significant association" is found. This is not surprising given the relatively small sample size and the (for me) expected polygenic nature of intelligence, but it (along with previous negative findings) tends to rule out any significant role for common variants of large effect in determining IQ.

The study uses SNPs across the genome to measure this relatedness and then shows it correlates with phenotypic similarity – i.e., the trait is heritable. We knew that already.

What they claim is that you can break down this effect by chromosome or by subregion. When they use the SNPs along longer chromosomes they seem to get a bigger effect – “explaining more of the phenotypic variance”. The inference is that thousands of SNPs, scattered across the whole genome, contribute to the trait or, more specifically to variance in the trait across the population (the implication is that they contribute to the value of the trait in individuals).

There is an alternative explanation for this effect, however, which is that using more SNPs simply gives a better estimate of genetic relatedness. So, the SNPs on chromosomes 1 (the longest) give a better estimate than those on chromosome 21 (the shortest) – they index relatedness with more precision. As a result, they correlate better with phenotypic similarity – this looks like you have “explained more of the variance”. In fact, getting such a signal from SNPs on chromosome 1 does not mean that any of the causal variants are actually on chromosome 1. Nor does the fact that such signals can be derived from anywhere in the genome mean that there are thousands of variants across the genome affecting the trait.

What Mitchell is claiming here is that the results could be explained by cryptic relatedness and/or population structure. However, the researchers address both issues, by excluding samples that appear to be related to other samples nearer than the level of 4th cousins and by including as covariates in their models the first few components of an MDS analysis. For non-close relatives in unstructured populations, how similar two individuals are on chromosome 1 tells us nothing about how similar they are on any other chromosome. Visscher was more explicit on this point in a commentary on the height paper:

What is the evidence that population structure is not causing the observed effects?

We took several steps to avoid population structure inflating the estimate of the variance explained by the SNPs. We excluded one individual from any pair that had an estimated relationship > 0.025 (approximately equivalent to between 3rd and 4th cousins). We fitted the first 20 principal components from the relationship matrix in the statistical model so that any population substructure that they picked up was excluded from the variance explained by the SNPs. Critically, we then estimated the correlation between the relationship matrices estimated from different chromosomes and did not find significant correlation. We tested a set of SNPs that are ancestry-informative in Europe for association with height and did not observe inflation of the test-statistics.

For the purpose of this paper, we performed an additional simulation experiment (inspired by comments from Dan Stram) by assuming that the causal variants were all carried on one set of chromosomes (odd numbers) and another set of chromosomes (even numbers) carried SNPs from which we estimated relatedness. If there is structure in the population then this would imply that a pair of individuals that are closely related on odd chromosomes will also be closely related on even chromosomes. We used the observed genotype data of 3,925 individuals and 295K SNPs as the basis of the simulation, and simulated 1,000 causal variants on the odd chromosomes with a total heritability of 80%. Then we performed a restricted maximum likelihood (REML) analysis of the simulated phenotypes on the genetic relationship matrix estimated from the SNPs on the even chromosomes. The estimates and standard errors (SEs) from 10 simulation replicates are shown in Table 1. Since REML estimates of variance are always positive, if the true variance explained is zero, we expect half the replicates to return an estimate of 0.0 and half to return an estimate with mean value 0.8 times the standard error. This is exactly what happened. Therefore we conclude (again) that there is no structure in the data that would inflate the estimate of the variance explained by the SNPs.

Steve Hsu correctly points out:

If I understand correctly, you want to claim that the observed population variation could be due to a few rare variants of large effect. But then it would be surprising for this study to have found .5 of the total variation to be associated with SNPs — compare to earlier studies using twins/adoptions/siblings that found narrow sense heritability of about .6 or so. I would not expect the rare alleles you hypothesize to be in good LD with SNPs (which are designed to tag common variants), so we would expect to lose a big chunk of the .6 additive heritability.

For example, in the Visscher paper on height they had to hand wave about imperfect LD to recover the full .8 or so of heritability. In this case the global fit comes out very close to .6, which suggests common rather than rare variants (at least, they are well tagged by SNPs). But if they are common variants their individual effect sizes must be small and there are a lot of them. Let me know if I am missing something.

Mitchell:

I don’t think the population variation is caused by “a few” rare variants – I think it is (or could be at least) caused by a larger number of rare variants – different ones in different people.

This is getting to be a pretty silly argument: "different ones in different people" would add up to a very large number, which sounds "polygenic" enough to me (regardless of how many people have the major allele at most variable sites). And again: rare variants will be tagged less effectively (if at all) by common SNPs, so the causal variants whose effects are being estimated in this study can't be too rare. The contribution of rare variants to variability in intelligence is likely largely on top of the effect identified here, and probably mostly negative: an unusually high number of rare, deleterious mutations will tend to interfere with brain development and diminish IQ; an unusually low number will result in a higher IQ on average, explaining at least in part the associations commonly found between intelligence and other markers of "good genes" (health, physical attractiveness, and so on). A priori, though, it makes no sense to expect this type of variation to be the only or overwhelming source of genetic variability in IQ. Clearly, a very large number of genes affect brain development, and I expect pretty much all of these genes to be polymorphic. It's also clear tradeoffs affecting IQ exist (such as between brain size and energy expenditure) and that specific IQ-influencing alleles will have varying effects on fitness in different times and places. So it seems obvious to me common variants should be expected to play a major role in inter-individual and inter-population IQ differences.

Incidentally, looking again at the supplementary material for the height paper recently, I noticed the following addition:

In the version of this supplementary file originally posted online, Supplementary Fig. 2a and 2b were incorrect. The legend stated that in Supplementary Fig. 2a, PC1 versus PC2 was plotted when in fact PC2 versus PC3 was shown. Similarly, in Supplementary Fig. 2b, PC4 versus PC5 was plotted rather than PC3 versus PC4 as stated. This error is purely graphical and does not in any way affect the results or conclusions presented in the article.

Dasein spotted the strange-looking PCA at the time. I didn't think it materially affected that paper's conclusion, but I'm pleased to see that confirmed and the issue resolved.

Y haplogroup R1b and light hair in Italy

Via Italian Wikipedia.

 

Update addressing some questions/comments:

(1) The map specifically shows the frequency of blond hair; so yes the frequency of light hair in general will be higher.

(2) The map is adapted from Biasutti's Razze e popoli della Terra. The data was originally collected by Ridolfo Livi in 1859-1863.

(3) The Biasutti/Livi map shows a higher frequency of blond hair in Corsica than in Sardinia. In keeping with the apparent pattern elsewhere in Italy, the frequency of R1b appears to be markedly higher in Corsicans than in Sardinians (in this paper, "HG 1" in combination with "HG 22" roughly corresponds to R1b).

(4) "Does R1b necessarily correlate with light hair?" In Italy it pretty clearly does. If you mean am I suggesting a strict correspondence between light hair and haplogroup R1b, obviously I am not. Looking at Europe as a whole, I doubt much of a correlation exists. But the evidence is consistent with the bearers of R1b (or more specifically subclades of R-L11) being lighter than the previous inhabitants of Italy. This doesn't mean the original carriers of R-M417 and some subclades of I weren't probably also lighter-haired, or that as R1b spread throughout Europe and mixing occurred, R1b always remained associated with light hair. It does tend to add yet more weight against attempts to link R1b in Europe to migration of Neolithic farmers from Anatolia, but dispensing with that question for good awaits large, high-resolution studies of ancient and modern DNA.

"haplogroup R1b is found in some of it's highest concentrations among European peoples in Spain and Portugal -- two countries hardly known for blondes."

Within Iberia, though, it's certainly possible the pattern will hold. Among Iberians, Basques have some of the highest frequencies of both R1b and blondism. According to Coon: 'The French Basques are by no means all brunet; Collignon finds 22 per cent of blue eyes, 44 per cent of "medium," and 34 per cent of dark. Black hair is found in 7 per cent of the group, brown in 77 per cent, and light brown to blond in 16 per cent. Among the Spanish Basques the incidence of blondism is somewhat lower, but the Basques are still light when compared to most other inhabitants of Spain.'

Variance of R-P312 lineages highest in eastern Europe

I take this as further evidence most R1b arrived in western Europe by way of eastern (but not southeastern) Europe:

Recently-revealed structure in Y haplogroup R1a

Posters at dna-forums.com using data from the 1000 Genomes Project to identify new Y subclades have arrived at the following structure below M417:

Early results from commercial and academic testing suggest the bulk of Central Asian, Middle Eastern, and South Asian R1a will turn out to be Z93+ and L342.2+. An academic, posting at dna-forums:

It appears that Z93 and Z95, which, according to the heuristic tree from the 1K genomes project, are above L342.2 do separate most of the Europeans who are ancestral for Z93 and Z95 from the Pakistanis, Indians, Iranians, Ashkenazi Levites and the Eastern Turks (probably Kurds). [. . .] We do have some very preliminary results on Z93 and Z95 that would indicate that almost all Balkan and East European R1a1's are ancestral for Z93 and Z95. Also most of Western Turkey but not Eastern Turkey. I think that the Tuscans who are derived for Z93 and Z95 must be originally of Ashkenazi ancestry (perhaps also the Iberian).

Note: Ashkenazi Levite R1a is L342.2+. I can see no reasonable grounds on which to propose the Z93+ L342.2- TSI and IBS samples are of Jewish origin. More from the academic:

Most Pakistanis are Z93/Z95. We haven't tested many Indians, but the few we have are Z93/Z95. We haven't genotyped any other Z or L SNPs on R1a1 backgrounds. What amazes me is the clear geographic bifurcation between Middle East/South Asian Z93/Z95 (and by inference L342.2) and European markers such as M458. This points to a vary old what we term vicariance pattern between Europe and the Middle East with respect to R1a1. Maybe the original source of R1a1 is somewhere in the middle such as Armenia or Turkey and some R1a1 moved to Europe to become M458 and other newly discovered L# lineages and other R1a1's move to Iran/Pakistan/India/Central Asia to become Z93/Z95. I think that this bifurcation occurred at least 10,000 years ago, but then of course we tend to use the evolutionary mutation rates on YSTRs.

Another poster points out: "Dividing by 3 [to bring the estimate more in line with real mutation rates] gives an age of 3300 years, almost exactly the estimate from Nordtvedt's spreadsheet." Someone else recently estimated the TMRCA for L342.2+ at around 3,600 years. So: if current patterns hold, the bulk of South Asian R1a unambiguously falls within European R1a variation. While I fully expect, when we eventually see results for these markers in large academic samples published, the papers will feature evolutionary mutation rates and less than parsimonious attempts to fit the distribution of M417 sublineages to archaeology, it's pretty clear to me Z93 and L342.2 originated on the Steppe within the past 4000 years or so and spread with Indo-Iranian.

Swedish McDonald's

Open thread (7)

Links, off-topic discussion, etc. Previous open threads: 1 2 3 4 5 6

Editorial and preliminary paper on People of the British Isles project

Both freely accessible.

A British approach to sampling:

The acronym ‘PoBI’ may not yet be familiar to human geneticists in the way that ‘HGDP’, ‘WTCCC’ or ‘HapMap’ are, but a paper in this issue of EJHG1 that introduces the ‘People of the British Isles’ project to the scientific community aims to change this. The PoBI project will collect up to 5000 DNA samples from diverse regions of the British Isles, taking great care to sample individuals with several generations of ancestry in rural locations. These samples are intended to serve as controls for future medical genetic studies, and to provide insights into the peopling of the British Isles over the last few millennia. [. . .] Although readers will have to wait for future publications to discover the insights from these large-scale genetic analyses, the current paper describes the sampling strategy and initial 3865 samples in some detail, outlines an approach to investigating fine-scale population structure using surnames, and presents some preliminary genetic analyses of a handful of chosen loci. [. . .]

In addition to collecting blood, the project recorded surnames. Using data from a census performed in 1881, these were classified as ‘local’ or ‘non-local’, and the two classes examined separately. The authors then modelled a population such as that from central England as a mixture between south-western (taken to represent Ancient Britons) and eastern (Anglo Saxon) populations, and estimated the contribution of each population to the central England autosomal genotypes. These contributions differed between the local surname class (mostly eastern) and the non-local class (half and half), which the authors take as evidence of subtle population structure. Published genetic analyses using much larger numbers of markers have already detected low, but significant levels of genetic structure within Britain in more straightforward ways,4, 5 even with less stringently ascertained samples (Figure 1): Europe-wide south-east to north-west gradients extend into the British Isles. We can look forward to deeper insights into genetic differentiation and its causes when large-scale genetic analyses of the PoBI samples are available.

[. . .] anthropological and evolutionary geneticists should rejoice in the assembly of this resource, the foresight of The Wellcome Trust in funding the project over a decade or so, and hope that resources are available for establishing more cell lines and performing more genome-wide sequencing, so that both the full set of samples and their sequences can be made widely available.

It is obvious why British people interested in their ancestry, and medical geneticists working with British subjects should welcome PoBI, but why should others pay attention? PoBI will not provide information about global genetic diversity in the way that HGDP7 and HapMap8 do, but its microcosmic survey of genetic variation in a set of small islands off the western coast of the Eurasian continent is revealing the level of differentiation that builds up over millennia via events well documented by archaeology and history, so these alternative data sets can be compared to address questions about the initial peopling of the area, and its subsequent reshaping by internal and external forces. And if the characteristics of the British – politeness, eccentricity, or drunken loutishness, according to your viewpoint and experience – have any genetic basis, perhaps PoBI can provide a starting point for identifying it! 

People of the British Isles: preliminary analysis of genotypes and surnames in a UK-control population:

There is a great deal of interest in a fine-scale population structure in the UK, both as a signature of historical immigration events and because of the effect population structure may have on disease association studies. Although population structure appears to have a minor impact on the current generation of genome-wide association studies, it is likely to have a significant part in the next generation of studies designed to search for rare variants. A powerful way of detecting such structure is to control and document carefully the provenance of the samples involved. In this study, we describe the collection of a cohort of rural UK samples (The People of the British Isles), aimed at providing a well-characterised UK-control population that can be used as a resource by the research community, as well as providing a fine-scale genetic information on the British population. So far, some 4000 samples have been collected, the majority of which fit the criteria of coming from a rural area and having all four grandparents from approximately the same area. Analysis of the first 3865 samples that have been geocoded indicates that 75% have a mean distance between grandparental places of birth of 37.3 km, and that about 70% of grandparental places of birth can be classed as rural. Preliminary genotyping of 1057 samples demonstrates the value of these samples for investigating a fine-scale population structure within the UK, and shows how this can be enhanced by the use of surnames.

Swedish population structure

Via Dienekes, The Genetic Structure of the Swedish Population:

An analysis of genetic differentiation (based on pairwise Fst) indicated that the population of Sweden's southernmost counties are genetically closer to the HapMap CEU samples of Northern European ancestry than to the populations of Sweden's northernmost counties. [. . .] We have shown that genetic differences within a single country may be substantial, even when viewed on a European scale.

The paper is in PLoS ONE (i.e., it's open access). More:

Few of whites' best friends are black

Friends for better or for worse: Interracial friendship in the United States as seen through wedding party photos (pdf):

Four findings stand out. First, the few survey estimates of close adult interracial friendships may overstate their actual prevalence, especially whites’ reporting of close friendships with blacks. My results show that very few whites have black friends who are close enough to be in their wedding party (3.7%), less than all previous estimates among adults. I reasoned that estimates of cross-race friendships for whites based on the wedding party photos would be lower than those based on existing survey measures because wedding parties include only the closest friends who may often have to conform to intergenerational norms about racial contact and the expectations of extended family. Wedding parties also limit the pool of friends to a small number and cannot be exaggerated out of normative pressure. Compared with what would be expected if there were homogenous opportunity for friendships, whites are most likely to have a close E/SE Asian friend and least likely to have a black friend. These results suggest that Jackman and Crane’s (1986: p. 460) declaration using data from 1979 still rings true: “only a tiny minority of whites could rightly claim that ‘some of their best friends’ are black.”

Second, I hypothesized that there would be an asymmetry, by race, of inviting a friend to be in the wedding party and being invited to be in a friend’s wedding party, with whites being invited more than they invite friends of other races. Adjusting for group size, whites and E/SE Asians are equally likely to invite and be invited, but whites invite blacks only half as much as blacks invite whites, and E/SE Asians invite blacks only one- fifth as much as blacks invite E/SE Asians. This finding is consistent with the notion that whites are less accepting of interracial friendships, a finding that is no longer detectable in survey-based attitudinal data.

More evidence of Sephardic ancestry in some new world Hispanic groups

Velez et al. The impact of Converso Jews on the genomes of modern Latin Americans. Hum Genet. 2011 Jul 26. [abstract]

Modern day Latin America resulted from the encounter of Europeans with the indigenous peoples of the Americas in 1492, followed by waves of migration from Europe and Africa. As a result, the genomic structure of present day Latin Americans was determined both by the genetic structure of the founding populations and the numbers of migrants from these different populations. Here, we analyzed DNA collected from two well-established communities in Colorado (33 unrelated individuals) and Ecuador (20 unrelated individuals) with a measurable prevalence of the BRCA1 c.185delAG and the GHR c.E180 mutations, respectively, using Affymetrix Genome-wide Human SNP 6.0 arrays to identify their ancestry. These mutations are thought to have been brought to these communities by Sephardic Jewish progenitors. Principal component analysis and clustering methods were employed to determine the genome-wide patterns of continental ancestry within both populations using single nucleotide polymorphisms, complemented by determination of Y-chromosomal and mitochondrial DNA haplotypes. When examining the presumed European component of these two communities, we demonstrate enrichment for Sephardic Jewish ancestry not only for these mutations, but also for other segments as well. Although comparison of both groups to a reference Hispanic/Latino population of Mexicans demonstrated proximity and similarity to other modern day communities derived from a European and Native American two-way admixture, identity-by-descent and Y-chromosome mapping demonstrated signatures of Sephardim in both communities. These findings are consistent with historical accounts of Jewish migration from the realms that comprise modern Spain and Portugal during the Age of Discovery. More importantly, they provide a rationale for the occurrence of mutations typically associated with the Jewish Diaspora in Latin American communities.

Sorbs autosomally distinct from Germans

Population-genetic comparison of the Sorbian isolate population in Germany with the German KORA population using genome-wide SNP arrays (abstract; provisional pdf):

Background
The Sorbs are an ethnic minority in Germany with putative genetic isolation, making the population interesting for disease mapping. A sample of N=977 Sorbs is currently analysed in several genome-wide meta-analyses. Since genetic differences between populations are a major confounding factor in genetic meta-analyses, we compare the Sorbs with the German outbred population of the KORA F3 study (N=1644) and other publically available European HapMap populations by population genetic means. We also aim to separate effects of over-sampling of families in the Sorbs sample from effects of genetic isolation and compare the power of genetic association studies between the samples.

Results
The degree of relatedness was significantly higher in the Sorbs. Principal components analysis revealed a west to east clustering of KORA individuals born in Germany, KORA individuals born in Poland or Czech Republic, Half-Sorbs (less than four Sorbian grandparents) and Full-Sorbs. The Sorbs cluster is nearest to the cluster of KORA individuals born in Poland. The number of rare SNPs is significantly higher in the Sorbs sample. FST between KORA and Sorbs is an order of magnitude higher than between different regions in Germany. Compared to the other populations, Sorbs show a higher proportion of individuals with runs of homozygosity between 2.5 Mb and 5 Mb. Linkage disequilibrium (LD) at longer range is also slightly increased but this has no effect on the power of association studies. Oversampling of families in the Sorbs sample causes detectable bias regarding higher FST values and higher LD but the effect is an order of magnitude smaller than the observed differences between KORA and Sorbs. Relatedness in the Sorbs also influenced the power of uncorrected association analyses.

Conclusions
Sorbs show signs of genetic isolation which cannot be explained by over-sampling of relatives, but the effects are moderate in size. The Slavonic origin of the Sorbs is still genetically detectable. Regarding LD structure, a clear advantage for genome-wide association studies cannot be deduced. The significant amount of cryptic relatedness in the Sorbs sample results in inflated variances of Beta-estimators which should be considered in genetic association analyses.