Man's Greatest Journey
Monday February 20, 2006
"DNA studies have confirmed this opening chapter of our story over and over: All the variously shaped and shaded people of Earth trace their ancestry to African hunter-gatherers, some 150,000 years ago." This quote from "The Greatest Journey" featured in the March 2006 issue of "National Geographic", sums up what I find so fascinating about genetic genealogy. That despite our great diversity of cultures, religions, races and beliefs, we are all related to one another.
Scientists have long believed that Africa was the earliest home of modern humans because that's where the oldest bones have been found. Now DNA is pointing to the same conclusion, pointing to Africa as the place where genetic markers began. In other words, the genetic makeup of humans from the rest of the world, is a subset of what is found in Africa.
The human genetic code, or genome, is 99.9 percent identical throughout the world. It is only in a small 0.1 percent portion of our DNA that the differences between individuals is found. Every once in a blue moon a small change or "stutter" occurs in this small section of DNA. Referred to as a marker, this mutation is then passed down to all of that person's descendants. Finding a similar mutation, or marker, in two people's DNA means that they share an ancestor somewhere in the distant past. Because of this, genetic mutations in our DNA can be used to trace our ancestors journeys through time and across the continents.
According to the "National Geographic" article, the earliest known hereditary mutation to spread outside of Africa is M168. This marker, which arose about 50,000 years ago, is found in all non-Africans. About 40,000 years ago, the M9 marker, common in Eurasians, appeared in the Middle East or Central Asia. The M3 marker is found in most Native Americans, who descend from the Asian population that reached the Americas about 15,000 - 20,000 years ago.
It's a fascinating article, but most is only available in the print version. I recommend you check it out at your local library or bookstore if you get the chance! You can also explore a lot of this information on the Web site of the Genographic Project.
Scientists have long believed that Africa was the earliest home of modern humans because that's where the oldest bones have been found. Now DNA is pointing to the same conclusion, pointing to Africa as the place where genetic markers began. In other words, the genetic makeup of humans from the rest of the world, is a subset of what is found in Africa.
The human genetic code, or genome, is 99.9 percent identical throughout the world. It is only in a small 0.1 percent portion of our DNA that the differences between individuals is found. Every once in a blue moon a small change or "stutter" occurs in this small section of DNA. Referred to as a marker, this mutation is then passed down to all of that person's descendants. Finding a similar mutation, or marker, in two people's DNA means that they share an ancestor somewhere in the distant past. Because of this, genetic mutations in our DNA can be used to trace our ancestors journeys through time and across the continents.
According to the "National Geographic" article, the earliest known hereditary mutation to spread outside of Africa is M168. This marker, which arose about 50,000 years ago, is found in all non-Africans. About 40,000 years ago, the M9 marker, common in Eurasians, appeared in the Middle East or Central Asia. The M3 marker is found in most Native Americans, who descend from the Asian population that reached the Americas about 15,000 - 20,000 years ago.
It's a fascinating article, but most is only available in the print version. I recommend you check it out at your local library or bookstore if you get the chance! You can also explore a lot of this information on the Web site of the Genographic Project.
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