Humans migrated from Africa more recently than thought

Our early human ancestors migrated out of Africa more recently than thought, between 62,000 and 95,000 years ago, according to a new study.
The findings contradict a recent study that put humans' first exodus from Africa at least 200,000 years ago.
The new results "agree with what we know from archaeology," said study co-author Alissa Mittnik, a biologist at University of Tubingen, in Germany.
Scientists have long debated when the first humans emerged from Africa to colonise the world.
All of the estimates hinge on one number: the gene mutation rates. By knowing how often genes change, and then counting up the number of genetic differences between different species or groups of people, scientists can create a "molecular clock" to decipher how long ago they shared a common ancestor, LiveScience reported.

Early studies used genetic differences in mitochondrial DNA - genetic material inside the cells' energy-making structures that gets passed on from mother to child - between chimpanzees and humans.

But since that technique is based on the number of mutations divided by the time since the two shared a common ancestor, it requires an estimate of when the common ancestor of chimpanzees and humans lived.
Newer research estimated the mutation rate in modern human families based on DNA from the nucleus, which involved another way of getting at the common ancestor timing.
That method suggested humans were racking up genetic mutations at half the rate - meaning to reach the genetic differences we see today humans would've had to leave Africa more than 200,000 years ago.

But that didn't jive with archaeological and other evidence, Mittnik told the website.
Researchers extracted mitochondrial DNA from 11 ancient human fossil skeletons from Europe and Asia. Using radioactive carbon dating, the oldest was estimated to be 40,000 years old, while the most recent came from medieval times.
The team found a mutation rate suggesting that humans left Africa between 62,000 and 95,000 years ago.
The researchers estimate that in its effort to avoid false positives (mutations that weren't really mutations), the nuclear DNA method missed quite a few real mutations.
That would lead to an underestimate of the mutation rate and a longer estimate for when humans left Africa, diverged from Neanderthals, and other things.

The study was published in the journal Current Biology.