Posted on 02/22/2008 11:13:14 AM PST by blam
Ancient 'Out Of Africa' Migration Left Stamp On European Genetic Diversity
Scientists compared more than 10,000 sequenced genes from 15 African-Americans and 20 European-Americans. The results suggest that European populations have proportionately more harmful variations, though it is unclear what effects these variations actually may have on the overall health of Europeans. (Credit: iStockphoto)
ScienceDaily (Feb. 22, 2008) — Human migration from Africa to Europe more than 30,000 years ago appears to have left a mark on the genes of Europeans today.
A Cornell-led study, reported in the Feb. 21 issue of the journal Nature, compared more than 10,000 sequenced genes from 15 African-Americans and 20 European-Americans. The results suggest that European populations have proportionately more harmful variations, though it is unclear what effects these variations actually may have on the overall health of Europeans.
Computer simulations suggest that the first Europeans comprised small and less diverse populations. That would have allowed mildly harmful genetic variations within those populations to become more frequent over time, the researchers report.
"What we may be seeing is a 'population genetic echo' of the founding of Europe," said Carlos Bustamante, assistant professor of biological statistics and computational biology at Cornell and senior co-author with Andrew Clark, a professor of molecular biology and genetics.
"Since we tend to think of European populations as quite large, we did not expect to see a significant difference in the distribution of neutral and deleterious variation between the two populations," said Bustamante. "It was quite surprising, but when we cross-checked our results to data sets gathered by other groups, we found the same trend."
The researchers focused on single nucleotide polymorphisms (SNPs), where a single DNA base pair (the smallest structural unit) in a gene's sequence had been altered. Genetic variations were classified as to whether a SNP was found in one or both populations. Some of these genetic changes led to amino acid changes in the proteins that the genes express, while others had no effect.
Collaborators at Max Planck Institute in Tübingen, Germany, and Harvard Medical School analyzed the amino acid changes and used a computer algorithm to predict whether the changes alter a protein's structure or function, and classified the changes into three categories: benign, possibly damaging or probably damaging.
Using that information, the Cornell group found that the European sample, while showing overall less genetic variation, had proportionately more amino acid changes and proportionately more harmful amino acid single nucleotide polymorphisms than the African sample.
"It's difficult to tell what the precise impact that a higher proportion of deleterious single nucleotide polymorphisms in the population will have on the average person's health," said Kirk Lohmueller, a graduate student in both Bustamante's and Clark's labs and the paper's lead author. "More detailed studies that involve sequencing many individuals both with and without certain diseases would better enable us to get at this question."
Future research may also reveal similar signatures as other populations left Africa for other geographic destinations.
Other Cornell co-authors include Amit Indap, Adam Boyko and Ryan Hernandez as well as Rasmus Nielsen, a former Cornell faculty member now at the University of Copenhagen, and Melissa Hubisz, a former Cornell programmer now at the University of Chicago. Celera Diagnostics performed the gene sequences.
The study was funded by the National Institutes of Health and National Science Foundation.
Adapted from materials provided by Cornell University.
Thanks for the link Blam. Describes me to a “T” - or most of it anyway.
I know that there are hints of a “bottle neck” in the human population in the ancient past. Probably, Ice Age climate change caused humans to drop down to less than 10K and perhaps as few as a few hundred world wide.
A smaller base population in the colder climates of Europe would cause less diversity there. Some have suggested that this also caused selection for higher intelligence and other cultural and genetic changes in order to survive the near extintion level conditions.
This is esoteric and highly speculative stuff. Trying to read into it is tough, and not exactly responsible science.
However, I think it is interesting to bring up that we all evolved from an original African population.
For a moment, I thought this thread was another story about black leftist college professors still promoting the “White Man stole mathematics from the Black Man” theory. What a relief!
I agree, the premise is not good.
“What is interesting to note is that the agricultural technology spread much further than the people who first ‘invented’ it.”
Well, my family’s E3b made it to Aberdeenshire, Scotland. Maybe the majority of agriculture E3b people died off in one of the plagues or by the hands of the Vikings.
It depends on how well the study was structured and conducted.
SMALL SAMPLE sizes
INCREASE
the significance of what’s found.
It’s greatly easy, all other things being equal, to find subtle changes at levels of statistical significance in large samples.
Whether those statistically significant findings from large samples mean anything or not is often dubious.
Ultimately the human species originated in Africa.
The discussions center around the when and how.
Nope. They're still there. There never was very many of them.
yeah, that was the first thing I noticed, then I saw the leap they made from African-American and European American to strictly Europeans. The test group is too small, there is no control group, and the group tested cannot be guaranteed 100% African or 100% European. As far as I can see it’s all wishful thinking on someone’s part.
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