Posted on 12/19/2005 2:52:15 PM PST by 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)
GGG Ping?
Dawkins will not be pleased.
Why are there no transitional species - if Evolution is true there should be some species that are not complete ... like Democrats, forinstance .....
Some religeous idiot will do a bible quote.
I see precious few quotes from Darwin around here, except for the purposes of derision.
ML/NJ
If you buy into the premise of the book "The Bell Curve," from about 15 years ago, it appears we citizens of the USA are evolving furiously, and most of the important evolution has taken place since World War I. Our meritocracy, which the USA has been (more or less) since roughly the end of WWI, is producing a much higher percentage of intelligent folk than has ever been seen in the history of any human society. At any rate, news like this shouldn't be considered particularly surprising, since it seems to be rediscovered every 5 - 10 years.
Hmmm. More evolutionary claptrap.
Let's run it through the mechanics of evolution and see if it makes any sense. 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.
Sorry, guys, doesn't wash. Evolution requires a LOT of death and survival of the fittest. (Darwin: "Nature is red in tooth and claw"). And if the offspring of BOTH survive together and can ultimately interbreed, evolution hasn't occurred at all.
Evolution always comes down to speculation and comes up short on evidence.
Just because they grew crops doesn't mean they quit hunting. Its not an either/ or situation.
And so what random genetic mutation occurred and how did it manifest? The gene for hunting AND farming behavior?
See, the problem with evolutionists is that their theory demands brutal rationality (ie, survival of the fittest), but when you point out the stark reality of a particular change -- like settling down to farm, losing body hair, inability of humans to smell or hear well, or even the dilution of a creature's genes through sexual reproduction -- there is always an exception or "possibility" thrown up to save the theory.
This is smoke and mirrors, nothing more. It comes down to a persistence to deny the existence of God and postulate that life "sprang" into existence. Not buying it.
Why would there be transitional species?
Because evolution doesn't happen in huge multi-gene mutational leaps. C'mon man, you know that!
If Evolution is true, then species are continually evolving ... and if so, there has to be species going from one thing to another ... like ocean to land or land to air .... something .... if you look at every living thing you'd notice they're complete ... a fruit fly will not evolve into an elephant or a rose into a fir tree ...
Sure, but the successful ones survive. Besides that, most all the evidence gets eaten.
There are plenty of species around now, and plenty of them are related to us. Even the plant kingdom is related to us. Any intermediate steps would have been localized in small populations except for the ones that were successful, and most of the intermediate steps would have disappeared. Life has a way of disposing of its ancestors, leaving nothing.
Tortured logic.
"I know what the theory of evolution says about survical of the fittest, but could not an intelligent designer be changing us and all other species for survivability in any new environment to which any species may venture?"
Well it's not doing a very good job, the vast majority of species are extinct.
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