Scientists have discovered the first solid evidence of an early African migration wave out of Africa that aimed straight for India, Asia and Australia. The clue to the 60,000-year-old migration is a natural "tag" in the microchondrial DNA of people in Ethiopia, India and eastern Asia, say scientists whose work appears in an issue of the journal Nature Genetics.

Mitochondria are the powerhouses of our cells, and carry their own DNA which changes at theoretically predictable rates and can be used to trace lineages of not only the mitochondria, but also the people who carry them.

"What you have is a pattern (of lineage) emerging," says anthropologist Clark Howell from the University of California at Berkeley, "more explicitly than was the case before."

Over the past several years many researchers have concentrated on the problem of when humans first left Africa and by what route. Fossil evidence suggests that the first modern African migration route out of Africa extended northward around what is now known as the eastern Mediterranean and Greece more than 100,000 years ago. 

But the mitochondrial DNA study is the first evidence that Africans made their way far beyond Africa and on to the rest of Asia, Australia and Pacific islands. The emigrants would have probably traveled from then present day Ethiopia region over a land bridge at the southern end of the Red Sea and then up through Saudi Arabia.

From there, the emigrants probably kept venturing east, staying south and away from the very cold northern regions then already occupied by Neanderthals.

Such a southern emigration route from Africa could explain how humans occupied Australia so early, says one of the study's authors, Silvana Santachiara-Benerecetti of the University of Pavia in Italy. "I think that the data seem good," says Luca Cavalli-Sforza, a geneticist from Stanford University.

There is a lot of similar research being done and the full story of early Africa exoduses will probably get clearer very soon as this work is confirmed by other scientists, he said. These mitochondrial studies of modern humans are separate from anthropological digs establishing that extinct ancestors of humans inhabited Africa 4 million years ago.

This report is from December 2, 1999 and is also listed in the publication journal Nature Genetics.