only the smart ones left...
Posted on 02/20/2008 2:42:03 PM PST by blam
Gene studies confirm "out of Africa" theories
By Maggie Fox, Health and Science Editor
WASHINGTON (Reuters) - Two big genetic studies confirm theories that modern humans evolved in Africa and then migrated through Europe and Asia to reach the Pacific and Americas.
The two studies also show that Africans have the most diverse DNA, and the fewest potentially harmful genetic mutations.
One of the studies shows European-Americans have more small mutations, while the others show Native Americans, Polynesians and others who populated Australia and Oceania have more big genetic changes.
The studies, published in the journal Nature on Wednesday, paint a picture of a population of humans migrating off the African continent, and then shrinking at some point because of unknown adversity.
Later populations grew and spread from this smaller genetic pool of founder ancestors -- a phenomenon known as a bottleneck.
Populations that remained in Africa kept their genetic diversity -- something seen in many other studies.
"The one thing that I think we cannot say from this study is that any one person's genome is any healthier or evolutionarily fit than another person's genome," said Carlos Bustamante of Cornell University in New York, who worked on one study.
"You have to think of this at the population level," Bustamante said in a telephone interview.
Bustamante's team has been looking at the DNA sequences of 15 African-Americans and 20 European-Americans, examining tiny one-letter changes in the DNA code called single-nucleotide polymorphisms or SNPs (pronounced "snips").
FIT OR EXTINCT
They tested these changes to qualify them as benign, or potentially affecting genes, amino acids and eventually proteins in a way that could damage health or make people less "fit" -- in evolutionary terms, less likely to survive and reproduce.
"Like every other study ... the African-American panel as a whole showed more variation than the European-American panel," Bustamante said.
Then his team did a computer simulation of a bottleneck, and found it predicted this pattern.
Bustamante said it is possible some of the SNPs are beneficial, and he said his team and others should compare the genetic changes they found to known genetic changes linked with diseases.
"I wish we had done that (already)," he admitted.
In the other study, Noah Rosenberg and colleagues at the University of Michigan and the National Institute on Aging analyzed DNA from 485 people around the world.
They looked for three types of genetic variation, including SNPs and larger changes that involve duplications, deletions and repetitions of large segments of DNA.
The patterns they found produced what they call the highest-resolution map yet of human genetic variation.
They also reinforce the idea that humans originated in Africa, then spread into the Middle East, followed by Europe and Asia, the Pacific Islands and finally to the Americas.
"Diversity has been eroded through the migration process," Rosenberg said in a statement.
People of African descent are the most genetically diverse, followed by people from the Middle East, and then Asians and Europeans. Native Americans resemble one another the most on a DNA level.
The study also found it is sometimes possible to trace a person's ancestry to a small group within a geographic region.
(Editing by Cynthia Osterman)
GGG Ping.
Love that grammar.
bfl
Here we go again. For years they have been trying to prove my ancestors did not arrive on the great ice ship. Still no proof they hadn’t.
Guess those Chinese supporters of parallel evolution of Homo Sapiens aren’t going to be too happy with this.
This is really stupid .... .
I suppose Africans are still “evolving”?
LOL!
I was wondering how that would have gone over with my old high school English teacher.
So I guess the Africans now have a “right” to all the land in the world. That’ll tick the Mexicans off.
Turns out that we are ALL African-American. I know that from now on when I fill out those government forms I am checking that box and daring them the prove otherwise.
This is why Africa leads the world in culture, economics, respect for individual liberty, etc... /s
Given the degree of horrific violence, the smartest ones left. Those left behind have some evolving left to do.
You’re too funny ... that “horrific violence” still goes on ... without “evolution” by many races ... .
only the smart ones left...
Actually a guy I work with (white, blond, from Minnesota) did that on a company form. The HR office gave him a hard time and he stood his ground. The HR office finally dropped the issue and let his claim stand. He was just annoyed that all those forms want to know "race."
My fiction (sci-fi, horror, etc) has the same irony.
That’s funny!
I was wondering how that would have gone over with my old high school English teacher.
If he knew his stuff, he'd have no problem. "more" modifies the word omitted (mutations)--"more small mutations ... more large mutations." One group has more mutations which are small; the other group has more mutations which are large.
This should not be confused with the comparatives of small or large (smaller, larger). Such a substitution results in a different statement.
"One group has smaller mutations; the other group has larger mutations"
...which says nothing about the relative number of such mutations. Clear?
people in white lab coats with test tubes is not a basis for reality.
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