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© UnknownEarly man: A third of people in modern Europe show genetic traces of populations from sub-Saharan Africa, leading researchers to conclude that people migrated between the continents as early as 11,000 years ago.
People moved between Africa and Europe long before recorded history - and the migrations might have been driven by Europeans moving south to 'weather' ice ages.

The genetic traces of long-forgotten migrations from Africa to Europe live on in Europeans today.

A third of the genetic traces of sub-Saharan lineages in today's Europe come from prehistory.

Researchers think that Europeans 'pushed south' by glaciers might have met with populations from sub-Saharan Africa.

People moved between the continents as early as 11,000 years ago.

Geneticists used mitochondrial DNA to look for the traces of ancient migrations.

Mitochondrial DNA is passed directly from mother to child with no DNA from the father - and tiny changes in the sequence come to 'characterise' different populations, which can be used to trace movements and migrations of groups of humans in the past.

Large numbers of people moved between Africa and Europe during recent and well-documented time periods such as the Roman Empire, the Arab conquest, and the slave trade - but the researchers found that a third of sub-Saharan lineages came from before these movements.

'It was very surprising to find that more than 35 percent of the sub-Saharan lineages in Europe arrived during a period that ranged from more than 11,000 years ago to the Roman Empire times,' said Dr. Antonio Salas of the University of Santiago de Compostela and senior author of the study.

'The other 65% of European haplogroup L lineages arrived in more recent times.'

The authors explain that these contacts likely connected sub-Saharan Africa to Europe not only via North Africa, but also directly by coastal routes.

Salas said that it still remains unknown why there was genetic flow between the Africa and Europe in prehistoric times.

One possible scenario is that some bidirectional flow was promoted when the last glaciation pushed some Europeans southward, until the glacier receded and populations returned north.

In addition to tracing the genetic links of Africa and Europe back to prehistoric times, Salas expects that their work will also help those individuals who want to learn more about their own ancestry.