Fact For Theory

[A_Wanderer]

A comprehensive scan of the human genome finds that hundreds of our genes have undergone positive natural selection during the past 10,000 years of human evolution.
...
Researchers from the University of Chicago analyzed the genomes of 209 unrelated individuals from three distinct human populations: East Asians, Europeans and Yorubans from Nigeria. Each population contained roughly 250 positively selected genes; however, most of the affected genes differed depending on the group.
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The new study links genetic changes to major events in the history of our species.

“There have been a lot of recent changes—the advent of agriculture, shifts in diet, new habitats, climatic changes—over the past 10,000 years," said Jonathan Pritchard, a human geneticist at the University of Chicago who led the study.

Many genes were found to be evolving in all three of the human populations studied. The specific functions of many of the genes are not known, but the researchers were able to separate them into broad categories. These categories include:

* Olfaction: the researchers found many genes important for taste and smell
* Reproduction: involved in things like sperm mobility and egg fertilization
* Increasing brain size
* Bone development and skeletal changes
* Carbohydrate metabolism: positive selection was observed for genes involved in breaking down mannose in Yorubans, sucrose in East Asians, and lactose for Europeans. (Mannose is a sweet secretion found in some trees and shrubs, sucrose is common table sugar, and lactose is a sugar found in milk.)
* Disease resistance and pathogen protection
* Metabolism of foreign compounds, such as exotic plant proteins or animal toxins

The researchers also found positive selection in four pigment genes important for lighter skin in Europeans that were not known before. Scientists think humans evolved lighter skin in Europe as an adaptation to less sunlight.

And in East Asians, they found strong evidence of positive selection in genes involved in the production of alcohol dehydrogenase (ADH), a protein necessary for breaking down alcohol. Many East Asians can't metabolize alcohol because they carry a mutation that prevents them from making ADH. The new finding suggests that the mutation may confer some currently unknown additional benefit.

The study, which used data collected by the International HapMap Project, is detailed in the March 7 issue of the journal Public Library of Science-Biology.

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[financeguy]

That figures, most of the Asians I know collapse after about three Jamesons

 

[najeena]

As much as all humans are similar, it's fascinating to learn how the small differences between us came about, and why. Some would say that God created us to be minutely different in ways, but evolutionary changes in response to climate and environment make so much sense.

 

[A_Wanderer]

As much as all humans are similar, it's fascinating to learn how the small differences between us came about, and why. Some would say that God created us to be minutely different in ways, but evolutionary changes in response to climate and environment make so much sense.

These quantifiable differences are important, especially in terms of genetic predispositions to certain diseases; the issue of what constitutes a subspecies on a genetic level is open for debate but an overarching factor must be that differences do not infer a heirachy of mankind. Bulk differences in IQ and physical prowess on a population scale do not detract from individual genetic potential.

 

[JCR]

The genes WILL tell.
And I can't wait for the rest of the story.
I recall a paleontological study on early hominids that determined there was a correlation between increase in brain size and meat eating. The idea was that the increase of protein in the diet aided in the evolution of brain size.


I feel somethin' twitchin' but it ain't my ovary.
(I have no idea what that means or why I said it)
Got that impulsivity gene?