Thursday, November 16, 2006

NYT's Nick Wade excerpt on race

Re-reading NYT's science reporter Nicholas Wade's Before the Dawn, the following excerpt (p194) struck me as both profound and obvious:
But the existence of considerable variation between races should not be any surprise either, given that the human family has long been split into separate branches, each of which has evolved independently for up to 50,000 years or more, buffeted in different directions by the random forces of genetic drift and the selective pressures of different climates, diseases, and societies.
Humans, of course, are not exempt from evolutionary forces. Drift, mutation, and selection continue to apply to us. Ignoring this has disastrous consequences, from hampering efforts to get medicines to people who stand to benefit from them (BiDil, for example) to immigration policies, from affirmative action quotas to interventionist wars like Iraq. We reject human biodiversity at our own peril.

(Human biodiversity2)


Fat Knowledge said...

I read this book on your recommendation. Overall I thought it was good, but I wished it had more depth. I felt like he was making stronger conclusions then the data he presented warranted.

For example, I don't get why he believes that humans 50,000 years ago were very similar to the Khosan people today. Why wouldn't the Khosan have evolved and changed just like everyone else? They are fairly light skinned and he says that humans 50,000 years ago. If their skin changed color, why couldn't all of their other attributes change as well?

I agree with the quote you stated, but I think it is more difficult to know with a high degree of certainty what is caused by genes and what by environment. I think many people would say that basketball ability is greatly influenced by genes. As the book states, in the 1930s basketball was dominated by Jews. So, a casual observer might have thought that Jewish people had a genetic advantage to play basketball. Of course, that idea would be thought of as crazy today.

Also, I thought this was an interesting passage from the book: Fisher's major work The Genetical Theory of Natural Selection in 1929 developed the argument that genes for mental ability are more frequent among the wealth, who have fewer children. But there is no evidence from IQ test to suppose that human cognitive ability ifs falling, as Fisher predicted. Therefore, despite the apparent correctness of Fisher's premise, his conclusion of inexorable intellectual decline seems somehow to be false.

How do you explain this?

Oh, and now that you are on Blogger Beta, you might want to check out the label feature. I think you will find it allows you to categorize your posts very easily.

crush41 said...

He does state that the ancestral human population isn't accessible in any modern human population for the reasons you mentioned.

But he posits that the Khosians are the closest due to the least amount forced change by the environment. The Khoisans still use click sounds, which should logically be replaced as a society's lexicon becomes more complex, and they're one of the two groups is still nomadic. Also, skeletal remains of archaic humans are more similar to contemporary Khoisan than any other population. Their mitochondrial DNA is the most genetically diverse in the world.

Maybe it's for effect, too. I'm not qualified to say much else, other than it seems plausible to me.

I agree that it's hard, and made a lot harder due to the PC omerta on investigating these sorts of things.

The less specialized a sport (in terms of who understands/involves themselves in it), the more nature will play into it. Running is a better example than early basketball (it had only been around for a few decades at the time of Jewish dominance), which is in turn a better example than say fencing. Might more impoverished ethnic groups be better at fencing than whoever fences? Probably, but it's not something most people are introduced to.

Regarding the intelligence testing: The Flynn effect seems to be abating. Nutrition and better physical environment (the removal of lead, asbestos, etc) probably help offset the slide. And globally it is almost certainly falling now.

Re categorization: I'll look at it. I get stuck in my old ways, but it has to be less clunky than what I'm doing now.

crush41 said...

Labels. That's the way to go. Thanks.

JSBolton said...

From the Reuters report on the Paabo results:
"They said the Neanderthal sequences are 99.95 percent identical to human DNA sequences. This compares to about a 98 percent similarity between humans and chimpanzees..."
Unless I'm misreading this, they've got the difference between moderns and neanderthals at a figure considerably less than that which is given for the difference between the major races of today. 5% is less than 15%, of the within species genetic variation.

crush41 said...


Lewontin's 85%/15% split refers to the .01% of total genetic diversity within humans as a species, which I believe would make human races 99.985% the same. I wonder if they could speak? What advantage did their larger brains yield them?

Jane Hurst's study of an English family where several members had major speech impediments had only a single defective gene on the seventh chromosome (FOXP2).

JSBolton said...

From John Hawks Anthropology Weblog:
"Neanderal-human genome draft difference compared to the human-human difference. Here's a passage from p. 354 of Green et al. (2006):
[...] In this case, 7.1% of the divergence along the human lineage is assigned to the time subsequent to the divergence of the two human sequences. The average divergence time between alleles within humans is thus 459,000 years with a 95% confidence interval between 419,000 and 498,000 years. As expected, this estimate of the average human diversity is less than the divergence seen between the human and the Neanderthal sequences, but constitutes a large fraction of it because much of the human sequence diversity is expected to predate the human-Neanderthal split. "
So according to this article in Nature,Green...2006,
the different races used in the modern human reference sample, diverge nearly as much as moderns and archaics.
Lewontin's 85/15 breakdown would then really be close to 50/50, if only less-than-million-year-old genetic diversity were included.