London: The number of descendants of the first humans leaving Africa had once reduced to barely over 1,000 before they began to expand rapidly, a study has found.
The findings have been made by genome scientist Richard Durbin and his then research assistant Heng Li at the Wellcome Trust Sanger Institute near Cambridge.
The scientists discovered the population of the ancestors of modern Asian and European people dwindled to just 1,200 who were "actively reproducing". They also found that African populations crashed to around 5,700 people, Daily Mail reported Monday.
And, contrary to popular belief, the study revealed that these early humans continued to breed with sub-Saharan Africans until as recently as 20,000 years ago.
The scientists mined the publicly available DNA sequence of American biologist Craig Venter - who was one of the first to sequence the human genome - as well as the sequences from six other people.
The duo scientists were able to learn an entire population`s history by taking a person`s genome.
Geneticists, interested in looking back at human history, have traditionally compared DNA sequences from numerous people around the world to determine how different populations relate to one another and when they might have gone their separate ways.
They have now discoverd that part of a person`s genome - which stores hereditary information - can also be followed back in time to when just one version, a common ancestor, existed.