Civilisation Has Left Its Mark On Our Genes

New Scientist ^ | 12-19-2005 | Bob Holmes

[blam]

Civilisation has left its mark on our genes

22:00 19 December 2005
From New Scientist Print Edition
Bob Holmes

Darwin’s fingerprints can be found all over the human genome. A detailed look at human DNA has shown that a significant percentage of our genes have been shaped by natural selection in the past 50,000 years, probably in response to aspects of modern human culture such as the emergence of agriculture and the shift towards living in densely populated settlements.

One way to look for genes that have recently been changed by natural selection is to study mutations called single-nucleotide polymorphisms (SNPs) – single-letter differences in the genetic code. The trick is to look for pairs of SNPs that occur together more often than would be expected from the chance genetic reshuffling that inevitably happens down the generations.

Such correlations are known as linkage disequilibrium, and can occur when natural selection favours a particular variant of a gene, causing the SNPs nearby to be selected as well.

Robert Moyzis and his colleagues at the University of California, Irvine, US, searched for instances of linkage disequilibrium in a collection of 1.6 million SNPs scattered across all the human chromosomes. They then looked carefully at the instances they found to distinguish the consequences of natural selection from other phenomena, such as random inversions of chunks of DNA, which can disrupt normal genetic reshuffling.

This analysis suggested that around 1800 genes, or roughly 7% of the total in the human genome, have changed under the influence of natural selection within the past 50,000 years. A second analysis using a second SNP database gave similar results. That is roughly the same proportion of genes that were altered in maize when humans domesticated it from its wild ancestors.

“Domesticated” humans Moyzis speculates that we may have similarly “domesticated” ourselves with the emergence of modern civilisation.

“One of the major things that has happened in the last 50,000 years is the development of culture,” he says. “By so radically and rapidly changing our environment through our culture, we’ve put new kinds of selection [pressures] on ourselves.”

Genes that aid protein metabolism – perhaps related to a change in diet with the dawn of agriculture – turn up unusually often in Moyzis’s list of recently selected genes. So do genes involved in resisting infections, which would be important in a species settling into more densely populated villages where diseases would spread more easily. Other selected genes include those involved in brain function, which could be important in the development of culture.

But the details of any such sweeping survey of the genome should be treated with caution, geneticists warn. Now that Moyzis has made a start on studying how the influence of modern human culture is written in our genes, other teams can see if similar results are produced by other analytical techniques, such as comparing human and chimp genomes.

Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0509691102)

[verity]

I am perfectly comfortable with the concept of evolution through divine intervention. Of course, this is only an opinion.

[muir_redwoods]

"The docile, agricultural humans had an evolutionary advantage such that their docile, agricultural offspring outcompeted the offspring of the cunning, tough hunter/gatherers, who died off en masse leaving the meek to inherit the earth."

The "docile" agriculturist was able to store food and live densely with others and would have been more than a match for hunter/gatherer bands who also had to deal with periodic shortages with no stored food to draw on. Starvation and predation of the H/G were most likely the cause of the Agriculturists prevailing, not direct competition.

[SkyDancer]

Ok .... oil had to come from something/animal/fishes ... :)

[JTHomes]

The docile, agricultural humans had an evolutionary advantage such that their docile, agricultural offspring outcompeted the offspring of the cunning, tough hunter/gatherers, who died off en masse leaving the meek to inherit the earth.

It could have favored the planners, meek or not. A hunter wakes up, "me hungry, me go kill, me eat". That takes care of today. The farmer wakes up, sows his crop, and waits, while living off of last year's harvest which will carry him through the year. Of course, he still hunts too, but can take a day off from time to time to see a play or go to a museum. Less dangerous than hunting woolly mammoth.

[RightWhale]

where did the original molecules come from

That assume there was a where, which begs the question.

[SkyDancer]

but then I repeat myself ... did they "self" generate?
one wonders .... :)

[SkyDancer]

and if all that DNA stuff is true, then why are there bald men? If 80% of body heat goes out the head, then there should never ever be bald men .... evolution seems to work whenever it wants to ....and, it has to work all the time ... if not, poof ... we're all gonzo ....

[RightWhale]

If you heard the evolutionist on Coast last night, you would be questioning a lot. I bought his book a few months ago. He is the happiest man on earth because he has figured it out. He points out that DNA does not rule the cell, and he has a point because there are cells without DNA, without a nucleus at all, yet they are alive. He points out that intelligence does not originate in the nervous system because creatures, single cells, even plants, develop behavior without any nervous system. Can't think of a reason there must be electrons and protons, but we can make interesting, useful, and entertaining things out of them. At some point in our infinite regress to original causes we must come to a question for which there is no answer, which point varies with each person and at each moment of his intellectual development.

[SkyDancer]

Hi,
Well with all that I just say ok, if I'm wrong on Evolution and Darwinism then what am I out at the end of my life ... but on the other hand, if Creationism is true and in which I believe, then ......

Have a Merry Christmas and a Happy New Year ...

Regards,
Jane

[RightWhale]

Evolution is just an explanation as far as I am concerned--doesn't rise to the level of theory. It doesn't even rise to the level of imagination as shown in Genesis.

In the sense of the humble origin of the greatest advance of civilization--the star, the stable, the three gifts--Merry Christmas

[SkyDancer]

Thanks .... take care ....

[SunkenCiv]

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