Humans left Africa for a scampi supper

EARLY humans left Africa by crossing the Red Sea and were in Australia within 4,000 years, according to DNA analysis.

A team of international scientists, led by Glasgow University statistician Dr Vincent Macaulay, examined samples of DNA taken from the indigenous populations of India, Malaysia and Australia which enabled them to establish when humans first arrived in the area and plot a map of their likely route.

It is thought a "tribe" of about 2,000 men and women were driven by a shortage of their staple diet - shellfish - to leave Africa by crossing the Red Sea at its narrowest point, known as "the Gate of Grief", between 85,000 and 66,000 years ago.

Everyone in the world outside Africa is believed to be descended from just three women in this tribe which spread across the globe.

They migrated into southern India, arriving about 66,000 years ago, travelled through Burma, Thailand, Indonesia and Malaysia, which was then joined to Asia, and finally made an epic journey over the ocean to Australia about 62,000 years ago.

At the time, most of Europe and northern Asia was desert, tundra or covered in ice. But about 50,000 years ago, as the climate improved, a group travelled from southern Arabia into modern-day Turkey and then into Europe.

"Occasionally when DNA is copied from a mother to her child it mutates. We believe that mutation happens in a regular manner - it’s like a clock ticking away," explained Dr Macaulay.

"We can reconstruct a huge family tree and reconstruct where these mutations occurred. By counting them you can get an idea of how deep the tree is, how many generations it goes back. The mitochondrial DNA of everybody outside Africa goes back to three women. Apart from those three all of the other women’s mitochondrial DNA has died out."

Pressure on food resources is believed to be the likely reason why early humans decided to swim or use boats to cross the Red Sea, which at the time was much lower and would have only been a few kilometres across at the Gate of Grief.

Climate change had caused an increase in salinity in the Red Sea and this would have reduced the population of shellfish, which is thought to have been a major component of people’s diet.

It was previously thought that humans left Africa through the Sinai region, but the DNA dating method shows the exodus took place at a time when a massive desert covered almost all northern Africa and the Middle East, making this unlikely.