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:sister: Firstly, i would like to apologize mod if i post this in the wrong section.
I hear from the radio today that scientists have found out that most of the humans in this world originated from one woman and one man. Which in Africa (Adam and eve was put down on Earth and it was believe that the country was now called Africa).
source :
http://news.bbc.co.uk/1/hi/sci/tech/2909803.stm
A genetic study has shown that the oldest known human DNA lineages are those of East Africans. The most ancient populations include the Sandawe, Burunge, Gorowaa and Datog people who live in Tanzania.
Researchers found a very high amount of genetic variation, or diversity, between the mitochondrial DNA of different individuals in these populations.
Mitochondrial DNA is passed down exclusively through the maternal line. The longer a population has existed, the more variation accumulates in its DNA lineages.
"They are showing really deep, old lineages with lots of diversity. They appear to be the oldest lineages identified in Africa to date," said Dr Sarah Tishkoff, of the University of Maryland, US, who led the research.
Great resource
The so-called African Eve represents the ancestral mitochondrial genome that gave rise to all the different types seen in people today.
Several of the ethnic groups sampled in the study also live in countries surrounding Tanzania.
"It's entirely consistent with what we expected," said Dr Spencer Wells, a geneticist and author. "All the evidence is pointing to East Africa as the cradle of humanity."
Dr Wells added that the data ties in well with archaeological evidence of a long occupation of East Africa by modern humans and hominids.
But Professor Ulf Gyllensten, a molecular biologist at the University of Uppsala, Sweden, was cautious about claims that the oldest DNA lineages were confined to East Africa.
"I wouldn't be surprised if Dr Tishkoff has found old lineages there, but I think we're just skimming the surface," he said.
"Too little research has been done in Africa to get a clear picture. I don't know why, because it's clear there is a great resource of genetic diversity there," added Professor Gyllensten.
Dr Tishkoff's team have collected mitochondrial DNA samples from 1,000 Tanzanians since they began their research in 2001.
Although the data comes from groups living in Tanzania, the Burunge and Gorowaa migrated to Tanzania from Ethiopia within the last 5,000 years.
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Dr Tishkoff said Ethiopia was also a good candidate for the region where modern humans evolved.
One of the populations sampled in the study, the Sandawe, speak a "click" language like that of Khoisan people from southern Africa.
The Khoisan were previously thought to possess the oldest DNA lineages, but those of the Sandawe are older. This suggests southern Khoisan originated in East Africa, according to Dr Tishkoff.
"That is surprising, because it has been presumed that the oldest populations were in the south," said Professor Gyllensten. Some of the oldest modern human archaeological sites in Africa are in the south of the continent.
Dr Tishkoff said she planned to carry out further research to narrow down the most ancient East African lineages.
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source :
http://www.sciencedaily.com/releases...0310103042.htm
By analyzing the relationship between the geographic location of current human populations in relation to East Africa and the genetic variability within these populations, researchers have found new evidence for an African origin of modern humans.
The origin of modern humans is a topic that is hotly debated. A leading theory, known as "Recent African Origin" (RAO), postulates that the ancestors of all modern humans originated in East Africa, and that around 100,000 years ago some modern humans left the African continent and subsequently colonized the entire world, supplanting previously established hominids such as Neanderthals in Europe and Homo erectus in Asia.
In the new work reported this week, researchers Franck Prugnolle, Andrea Manica, and François Balloux of the University of Cambridge show that geographic distance from East Africa along ancient colonization routes is an excellent predictor for the genetic diversity of present human populations, with those farther from Ethiopia being characterized by lower genetic variability. This result implies that information regarding the geographic coordinates of present populations alone is sufficient for predicting their genetic diversity. This finding adds compelling evidence for the RAO model. Such a relationship between location and genetic diversity is indeed only compatible with an African origin of modern humans and subsequent spread throughout the world, accompanied by a progressive loss of neutral genetic diversity as new areas were colonized. The loss of genetic diversity along colonization routes is smooth, with no obvious genetic discontinuity, thus suggesting that humans cannot be accurately classified in discrete ethnic groups or races on a genetic basis.
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Franck Prugnolle, Andrea Manica and François Balloux: "Geography predicts neutral genetic diversity of human populations"
The other members of the research team include Franck Prugnolle, Andrea Manica, and François Balloux from the University of Cambridge. The research was supported by the BBSRC and a Lavoisier Fellowship from the Ministère Français des Affaires Etrangères (F.P.).
Publishing in Current Biology, Volume 15, Number 5, March 8, 2005, pages R159-R160.
http://www.current-biology.com
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and if you think this project is interesting... you can also participate in the project.
Please visit :
http://www.dnaancestryproject.com/yd...o_ancestry.php
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:sister: