A few abstracts

Eur J Hum Genet. 2008 Mar 5 [Epub ahead of print]

Quantifying the increase in average human heterozygosity due to urbanisation.

Rudan I, Carothers AD, Polasek O, Hayward C, Vitart V, Biloglav Z, Kolcic I, Zgaga L, Ivankovic D, Vorko-Jovic A, Wilson JF, Weber JL, Hastie N, Wright A, Campbell H.

[1] 1Department of Public Health Sciences, University of Edinburgh, Edinburgh, UK [2] 2Croatian Centre for Global Health, Split, Croatia.

The human population is undergoing a major transition from a historical metapopulation structure of relatively isolated small communities to an outbred structure. This process is predicted to increase average individual genome-wide heterozygosity (h) and could have effects on health. We attempted to quantify this increase in mean h. We initially sampled 1001 examinees from a metapopulation of nine isolated villages on five Dalmatian islands (Croatia). Village populations had high levels of genetic differentiation, endogamy and consanguinity. We then selected 166 individuals with highly specific personal genetic histories to form six subsamples, which could be ranked a priori by their predicted level of outbreeding. The measure h was then estimated in the 166 examinees by genotyping 1184 STR/indel markers and using two different computation methods. Compared to the value of mean h in the least outbred sample, values of h in the remaining samples increased successively with predicted outbreeding by 0.023, 0.038, 0.058, 0.067 and 0.079 (P<0.0001), where these values are measured on the same scale as the inbreeding coefficient (but opposite sign). We have shown that urbanisation was associated with an average increase in h of up to 0.08-0.10 in this Croatian metapopulation, regardless of the method used. Similar levels of differentiation have been described in many populations. Therefore, changes in the level of heterozygosity across the genome of this magnitude may be common during isolate break-up in humans and could have significant health effects through the established genetic mechanism of hybrid vigour/heterosis.European Journal of Human Genetics advance online publication, 5 March 2008; doi:10.1038/ejhg.2008.48.

PMID: 18322453 [PubMed - as supplied by publisher]

Coll Antropol. 2007 Dec;31(4):1135-41.

Anthropological analysis of neolithic and Early Bronze Age skeletons--a classical and molecular approach (East Slavonia, Croatia).

Hincak Z, Drmić-Hofman I, Mihelić D.

Institute for Mediterranean Heritage, Science and Research Center of Koper, University of Primorska, Koper, Slovenia. zdhincak@inet.hr

Theories about the first Indo-European migration are numerous. Significant contribution in attempt to resolve these theories is given by analysing skeletal material from two biggest prehistoric archaeological sites from N-E Croatia. Eight skeletons of Starcevo culture from sites "Nama" and "Hotel" at Vinkovci (6100-5500 BC) and seven skeletons of Vucedol culture from the site Vineyard Streim at Vucedol near Vukovar (3000-2500 BC) were analysed. Methods of classical anthropological analysis tried to distinguish the differences among members of both populations, while the methods of molecular genetics were used in defining possible genetic structure of both ancient populations. Established differences speak on the behalf of the theory of Maria Gimbutas about the first Indo-European migration with a cattle breeding population from the east around 3500 BC.

PMID: 18217472 [PubMed - indexed for MEDLINE]

BMC Evol Biol. 2008 Feb 29;8(1):75 [Epub ahead of print]

X-chromosome SNP analyses in 11 human Mediterranean populations show a high overall genetic homogeneity except in North-west Africans (Moroccans).

Tomas C, Sanchez JJ, Barbaro A, Brandt-Casadevall C, Hernandez A, Ben Dhiab M, Ramon M, Morling N.

ABSTRACT: BACKGROUND: Due to its history, with a high number of migration events, the Mediterranean basin represents a challenging area for population genetic studies. A large number of genetic studies have been carried out in the Mediterranean area using different markers but no consensus has been reached on the genetic landscape of the Mediterranean populations. In order to further investigate the genetics of the human Mediterranean populations, we typed 894 individuals from 11 Mediterranean populations with 25 single-nucleotide polymorphisms (SNPs) located on the X-chromosome. RESULTS: A high overall homogeneity was found among the Mediterranean populations except for the population from Morocco, which seemed to differ genetically from the rest of the populations in the Mediterranean area. A very low genetic distance was found between populations in the Middle East and most of the western part of the Mediterranean Sea. A higher migration rate in females versus males was observed by comparing data from X-chromosome, mt-DNA and Y-chromosome SNPs both in the Mediterranean and a wider geographic area. Multilocus association was observed among the 25 SNPs on the X-chromosome in the populations from Ibiza and Cosenza. CONCLUSIONS: Our results support both the hypothesis of (1) a reduced impact of the Neolithic Wave and more recent migration movements in NW-Africa, and (2) the importance of the Strait of Gibraltar as a geographic barrier. In contrast, the high genetic homogeneity observed in the Mediterranean area could be interpreted as the result of the Neolithic wave caused by a large demic diffusion and/or more recent migration events. A differentiated contribution of males and females to the genetic landscape of the Mediterranean area was observed with a higher migration rate in females than in males. A certain level of background linkage disequilibrium in populations in Ibiza and Cosenza could be attributed to their demographic background.

PMID: 18312628 [PubMed - as supplied by publisher]

[Note: This last looks like a pretty weak study--only 25 SNPs are examined. The provisional PDF is freely available.]

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