Posted on 03/19/2006 3:22:32 PM PST by blam
Evolution persisted in agricultural era
Bruce Bower
Natural selection continued to sculpt humanity's genetic identity after the Stone Age gave way to farming around 11,000 years ago, according to a new DNA analysis.
A team led by Jonathan K. Pritchard of the University of Chicago identified survival-enhancing gene variants that began spreading through human populations between roughly 10,800 and 6,600 years ago.
The scientists scanned the genomes of 89 East Asians, 60 Europeans, and 60 Africans to find DNA stretches recently affected by natural selection. Their technique exploits the tendency of DNA regions containing advantageous genes to spread quickly through populations and generate relatively few mutations.
More than 700 gene variants showed both those characteristics, Pritchard's group reports in the March PLoS Biology. Scientists know the function of some of the genes whose variants were identified.
Some of the genes influence fertility and reproduction, such as one that affects the protein structure of sperm in East Asians and Africans. Four other highlighted genes contribute to skin pigmentation in Europeans; mutations in those genes have been linked to disorders that cause unusually light pigmentation or albinism.
Recent natural selection also affected various genes involved in skeletal development in each population, the team reports.
Additional genes spread through populations after the advent of agriculture as people adapted to new kinds of food and colonized new areas, the researchers say. These include genes that contribute to the processing of lactose in Europeans, alcohol in East Asians, and dietary fatty acids in all three populations studied.
Several genes that affect the brain also responded to natural selection during agricultural times, the investigators say. However, they found no such evidence for two brain genes previously touted as subjects of recent natural selection.
(SN: 9/24/05, p. 206: Available to subscribers at http://www.sciencenews.org/articles/20050924/note16.asp).
GGG Ping.
YEC INTREP
You should probably be a bit more specific and say that MICROevolution continued into the last 15000 years or thereabouts.
That made-up word has no scientific value. Therefore, its use does not lead to being "more specific".
You're totally wrong on that and the definitions are simple enough and easy enough to comprehend. MACROevolution means the development of new kinds of organs and new basic plans and designs for existence. MICROevolution means anything less than that in the way of genetic change.
And you'll find that definition in exactly which scientific journal?
LOL. Wikipedia is NOT a scientific journal. Thanks for the laugh, though.
This chart suggests that you could be wrong.
Source: http://wwwrses.anu.edu.au/environment/eePages/eeDating/HumanEvol_info.html
Sorry if that took a second look. I'm not used to checking words I use with science journals or the people who run them. If I can find a word in dictionaries and encyclopedias, I feel pretty good about using it.
I have to correct my previous posting -- the complete term "micro evolution" yields 883 hits. Fewer than 321,000, but still more than zero.
The Neanderthal has been ruled out as a human ancestor for being too far genetically removed and every other hominid was further removed... The neanderthal was basically some sort of a glorified ape."
Welcome, newbie. None of that is true. Neandertal man wasn't "a glorified ape", any more than Neandertal man was a 18th century Cossack with rickets. There have been claims, based on fewer than 400 base pairs of mtDNA, that Neandertal was too far removed, but those claims are rubbish.
I don't think you understand how that chart works.
Inability to interbreed was once a "line", and once that was crossed, the line was moved by the proponents of "micro" and "macro" evolution in a vain effort to keep them separate. "Irreducible complexity" was once proposed as a "line" in regards to the flagella (and still is, on many creationist websites). That was proven false, and the line was once again moved by the proponents (at least the ones who did not ignore it completely). There are many other examples.
These terms are defined and redefined seemingly at the whim of the individual users, and with such frequency as to be irrelevant. They are not scientific terms.
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