( As the world's first explorers branched...)History-hunting geneticists can still follow familiar trail

Recently some scientists have raised doubts about this classic genetic system to study ancient migrations of people and to estimate the populations of people or animals as they existed tens of thousands of years ago.

But University of Florida researchers writing this month in an online edition of Science validate the approach, which involves tracking sequences of mitochondrial DNA, also known as mtDNA.

"The study of mtDNA has helped to demonstrate the African origin of our species and the relationship between living humans and the Neanderthals," said Connie Mulligan, an associate professor of anthropology in the College of Liberal Arts and Sciences and an assistant director of the UF Genetics Institute. "MtDNA data have also been used to establish the time and route of major events in human history, such as the expansion of Neolithic farmers into Europe, and the settlement of the New World."

MtDNA has made headlines recently because of initiatives such as the National Genographic Project, a multimillion-dollar endeavor to reconstruct humanity's ancient migrations, and because of well-publicized efforts to track the ancestral roots of Oprah Winfrey and other personalities.

Located within the hundreds of energy-producing mitochondria that lie outside the nucleus of our cells, mtDNA is unlike the DNA inside the nucleus of a cell that contains genes from both of our parents -- in people and animals mtDNA is exclusively passed from mothers to their children.

For humans, this means that all of the mtDNA in our cells are copies of our mothers' mtDNA, which in turn were copies of their mothers' mtDNA. In this way, mtDNA progresses through the ages, springing from what many scie
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Source:University of Florida