What were humans like 160,000 years ago?
Modern humans, homo sapiens, can trace our ancestry back through time to a point where our species evolved from other, more primitive, hominids. Scientists do not understand why this new type of human suddenly appeared, or how the change happened, but we can trace our genes back to a single female that is known as "Mitochondrial Eve".
Mitochondrial Eve (mt-mrca) [Right: An artist's rendition] is the name given by researchers to the woman who is defined as the matrilineal most recent common ancestor (MRCA) for all currently living humans. Passed down from mother to offspring, all mitochondrial DNA (mtDNA) in every living person is derived from this one female individual. Mitochondrial Eve is the female counterpart of Y-chromosomal Adam, the patrilineal most recent common ancestor, although they lived at different times.
Mitochondrial Eve is believed to have lived between 150,000 to 250,000 years BP, probably in East Africa, in the region of Tanzania and areas to the immediate south and west. Scientists speculate that she lived in a population of between perhaps 4000 to 5000 females capable of producing offspring at any given time. If other females had offspring with the evolutionary changes to their DNA we have no record of their survival. It appears that we are all descendants of this one human female.
Mitochondrial Eve would have been roughly contemporary with humans whose fossils have been found in Ethiopia near the Omo River and at Hertho. Mitochondrial Eve lived significantly earlier than the out of Africa migration which might have occurred some 60,000 to 95,000 years ago.
The region in Africa where one can find the greatest level of mitochondrial diversity (green) and the region anthropologists postulated the most ancient division in the human population began to occur (light brown). The ancient metropolis in located in this latter (brown) region which also corresponds to the estimated age when the genetic changes suddenly happened.
Could this be a coincidence?
