The findings also add new weight to theories that all human life began in Africa.

Academics from the University of Texas and their colleagues in China studied 28 population groups in China and concluded that most - if not all - had their genetic origins in Africa.

They looked at pieces of DNA known as microsatellites, which are short, repeating DNA segments that yield information about genetic variation among people.

The researchers found that all Chinese have a great deal in common genetically, although there are some regional variations.

Mythology holds that the Chinese are descended from a single ancestor

The findings, published by the National Academy of Sciences in Washington, supports what has come to be known as the "Out of Africa theory".

This theory contends that homo sapiens, the modern form of human life, is descended from a population of ancestors who migrated out of Africa about 100,000 years ago.

The new data also supports the idea of an "African Eve" who is an ancestor of all living humans.

The Eve hypothesis, first published in 1987, suggests that all human DNA can be traced back to a single female. This "Eve" would have lived in Africa about 200,000 years ago.

The latest research challenges an alternative theory which holds that several different groups of humans evolved separately at the same time in several places around the world.

Chinese mythology holds that the Chinese are descended from a single ancestor, the Yellow Emperor.