London, Sept. 30: Everyone in the world is descended from a single person who lived around 3,500 years ago, according to a new study.
Scientists have worked out that the most recent common ancestor of all six billion people alive today probably dwelt in eastern Asia around 1,415BC.
Although the date may seem relatively recent, researchers say that the findings should not come as a surprise.
Anyone trying to trace their family tree soon discovers that the number of direct ancestors doubles every 20 to 30 years. It takes only a few centuries to clock up thousands of direct ancestors.
Using a computer model, researchers from the Massachusetts Institute of Technology attempted to trace back the most recent common ancestor using estimated patterns of migration throughout history.
They calculated that the ancestor's location in eastern Asia allowed his or her descendants to spread to Europe, Asia, remote Pacific Islands and the Americas.
Going back a few thousand years more, the researchers found a time when a large fraction of people in the world were the common ancestors of everybody alive today ' while the rest were ancestors of no one alive. That date was 5,353 BC, the team reports in Nature.
The researchers, led by Steve Olson, stressed that the date was an estimate.
'Nevertheless, our results suggest that the most recent common ancestor for the world's current population lived in the relatively recent past ' perhaps within the last few thousand years,' he said.
He added: 'No matter the languages we speak or the colour of our skin, we share ancestors who planted rice on the banks of the Yangtze, who domesticated horses on the steppes of the Ukraine, who hunted giant sloths in the forest of north and south America and who laboured to build the Great Pyramid of Khufu.'
Although some groups of peo ple may have lived in isolation from the rest of the world for hundreds of years, the researchers say no one alive today has been untouched by migration.