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Human beings may have had a brush with extinction 70,000 years ago |
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Knowledge Base
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Written by team josh
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Saturday, 26 April 2008 |
 Today there are 6.6 billion people living on the earth. But there was a time when humans shrunk to as low as 2,000. In a new study, scientists have found that humans were forced to eliminated, before the race migrated outside of Africa and expanded its numbers.
Human beings may have had a brush with extinction 70,000 years ago, an extensive genetic study suggests. The human population at that time was reduced to small isolated groups in Africa - apparently because of drought - according to an analysis released Thursday.
The report notes that a separate study by researchers at US-based Stanford University estimated the number of early humans may have shrunk to as low as 2,000, before numbers began to expand again in the early Stone Age.
Previous studies using mitochondrial DNA – which is passed down through mothers – have traced modern humans to a single ‘mitochondrial Eve’, a female hominid who lived in Africa about 2,00,000 years ago.
The new study looks at the mitochondrial DNA of the Khoi and San people in South Africa, who appear to have diverged from other people between 90,000 and 1,50,000 years ago.
Eastern Africa experienced a series of severe droughts between 1,35,000 and 90,000 years ago. The researchers said this climatological shift may have contributed to the population changes, dividing into small, isolated groups which developed independently.
Paleontologist Meave Leakey, a Genographic advisor, commented: “Who would have thought that as recently as 70,000 years ago, extremes of climate had reduced our population to such small numbers that we were on the very edge of extinction.”
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