Remedial population genetics for Greg Cochran

From Graham Coop's population genetics notes:

1.4 Inbreeding

We can define an inbred individual as an individual whose parents are more closely related to each other than two random individuals drawn from some reference population. [. . .]

1.6 Summarizing population structure

We defined inbreeding as having parents that are more closely related to each other than two individuals drawn at random from some reference population. The question that natu- rally arises is: Which reference population should we use? While I might not look inbred in comparison to allele frequencies in the United Kingdom (UK), where I am from, my parents certainly are not two individuals drawn at random from the world-wide population. If we estimated my inbreeding coefficient F using allele frequencies within the UK, it would be close to zero, but would likely be larger if we used world-wide frequencies. This is because there is a somewhat lower level of expected heterozygosity within the UK than in the human population across the world as a whole.

Wright (1943, 1951) developed a set of ‘F-statistics’ (also called ‘fixation indices’) that formalize the idea of inbreeding with respect to different levels of population structure. He defined F XY as the correlation between random gametes, drawn from the same level X, relative to level Y.

[. . .] the reduction in heterozygosity within individuals compared to that expected in the total population can be decomposed to the reduction in heterozygosity of individuals com- pared to the subpopulation, and the reduction in heterozygosity from the total population to that in the subpopulation.


Anonymous said...

Damn dude, you're getting owned by Dr. Jayman and Dr. Gregory Cochran, how does that feel?

spagetiMeatball said...

Cochrane's gonna mop you up man.

Don't do it.

n/a said...

Recap for those with low comprehension:

- Greg Cochran attempted to white knight for "Dr. Jayman".

- I correctly surmised Cochran had no idea what argument he was actually interjecting himself into.

- I forced Cochran to acknowledge this.

Anonymous said...

What's the argument Cochran thought he was in, and what's the actual argument?

What did Cochran acknowledge?

pumpkinperson said...

I responded to Cochran's comments here:

Anonymous said...

LOL at Cochran's asslicking fanbois

Anonymous said...


Jo said...

off topic.

n/a said...

"What's the argument Cochran thought he was in, and what's the actual argument?"

JayMan linked to a table of coefficients of relationship (showing expected values under the assumption of no non-recent inbreeding) as "proof" ethnic genetic interests do not exist. I corrected him (populations are inbred relative to humanity as a whole), and also subsequently corrected him on the definition of "ethnic genetic interests".

Cochran thought he jumping into an argument about whether or not ethnocentrism could have evolved via group selection in humans.

After I prodded him for clarification of exactly what he thought he was weighing in on, he acknowledged the above by way of the post you link to (irrelevant to the original argument) and by directly misstating the meaning of "ethnic genetic interests" within the comment threads and then subsequently (after I again corrected him on the definition of "ethnic genetic interests") changing his argument to a mind-reading one, insisting no one can truly care about genetic similarity, and that the only possible real reasons I could prefer my own race over others relate to intelligence, creativity, etc.

As it happens, Cochran is also wrong to summarily dismiss any role of group selection in the evolution of altruism in humans (and I'd recommend reading Chuck's comments at the westhunt thread), but this is a separate argument that has no bearing on the original JayMan argument.

Anonymous said...

Cochran seems to be dismissing both group selection and genetic interests in that thread.

Anonymous said...

The mathematical extent of genetical overlap is not, by itself, going to give you any practical reason to favor or disfavor anybody. I mean, most of what you’re counting is stuff that doesn’t even code for anything: who cares?

This is the sort of thing I'd expect to hear from Tim Wise.

Even if one were to accept that only coding sequence matters, the same is also true for the DNA shared between parent and child. Should parents not care about their children because most of what they share is 'junk'? And people do care about the degree of relationship from an Fst of .15. No normal person wants their children to be childless.

Now if you’re saying that you like Bach, and you favor population policies that maximize the number of potential Bachs – then that’s what you like. But Fst isn’t going to tell you anything useful about that.

The allele frequency differences for an Fst of .15 may seem small, but added up over many sites, it's significant. Better add Edwards (2003) to genius Cochran's remedial reading list. Classical music developed in the West just as a matter of circumstance, yes?

And what if someone doesn’t like Bach? Telling him that he should like Bach, because he’s genetically closer to you than, say, Tojo, isn’t much of an argument

Because we can't agree on which musicians we like, there's not much of an argument against the immigration invasion. How convincing.

When someone as self-evidently brilliant as Cochran bitterly opposes something with nonsense, you have to ask why that is.

A couple theories:

1- Cochran is married to a non-white.

2- Cochran's ego and wallet are inflated by non-white fanboys like Dr. JayMan, misdreavus, and Razib Khan.

Anonymous said...

Cochran has received grants from the jew Ron Unz in the past and has a bunch of jewish readers in his audience thanks to his Ashkenazi IQ hypothesis.

Anonymous said...

Why didn't Harpending participate in this debate and discussion? He still blogs at West Hunter, and he worked on Salter's book.

M said...

Jewish and non-white dinner guests. Don't underrate the power of commensals to sway a man's opinions.

Anonymous said...

Interesting. I didn't know that Cochran received money from jew rku.

Funny too, given this comment:

GNXP's Razib says of Cochran, "Information technology is a deadly weapon in this man's hands. Greg Cochran is a genius, and he's got the 'fuck you' money to prove it."

n/a said...

Cochran, while receiving hundreds of thousands of dollars as an "Unz Fellow", didn't hold back from publicly trashing Unz's Hispanic IQ article. So the "'fuck you' money" comment may be fairly literally on the mark in Cochran's case.

Dinner guests and fan-boys: could be. Also the fact that he's apparently steeped in the racially universalist Christianity and science fiction of the last half of the twentieth century.

Mostly, I think he just hadn't seriously thought it through (what form selection for ethnocentrism would take, what sorts of traits would be selected for) and was certain he knew things that aren't actually true (that group selection couldn't be an important force in human evolution because the math doesn't work out; even though he's never worked out the math himself, and people who did, like W. D. Hamilton and Robert Axelrod, came to a very different conclusion).

Anonymous said...

Is Cochran religious?

n/a said...

Apparently, though I have no idea to what degree.

Anonymous said...

Why on earth would jew rku give Cochran 600K?

I seem to remember Harpending complaining some years back that no one would test their Ashkenazi intelligence hypothesis and that it would only take a few tens of thousands of dollars to do it (would be even cheaper now).

Anonymous said...

Is there a source on Cochran being religious?

He's pretty obvious about being into sci-fi and WWII history, but I haven't noticed him being into religion.

Anonymous said...

Cochran seems to be friends with Harpending, who has worked with Cochran and still blogs with him. Harpending worked on Salter's book and I believe he agrees with him. I wonder why Harpending didn't comment or blog on this issue at West Hunter.

Anonymous said...

Cochran is a malcontent blowhard who's motives and ideas often come down to trying to unnerve people and showing off just how much smarter he supposedly is than everyone else (an image he's developed in large part thanks to his spergy fanboys who've been telling him that over the years), and Jayman is just an annoying fat aspie.

Anonymous said...

Looks as if my transmission needs work. And dental crowns aren’t free.

Somewhere, rku smiles.

Anonymous said...

So Cochran never responded to or commented on this?

Does he not know or is he worried about being exposed?

How disappointing.

Anonymous said...

lol is cochran even trying anymore