Tuesday, June 11, 2013

Modern Humans Not in India Before Toba

Yes, I am taking a break from political stuff.  At times like this the blog becomes more a placemarker for stories which interest me personally.   Human Origins is one of them.   I am decidedly in favor of a more recent origin for humanity and for the genetic bottleneck which DNA sampling as determined narrowed our genetic diversity in the past.     One possible explanation for the bottleneck was a massive volcanic event called Toba.  This happened in India, roughly 70 thousand years ago.   Those arguing for a more recent origin of humans claimed that this was NOT the bottleneck event which our genes tell of, and that modern humans were not dispersed into Asia at that time.  The other side argued that they were, and that the Toba event was what winnowed the field.  This study of Indian DNA indicates that our ancestors had not made it to India at that time, supporting a more recent arrival of mankind and the bottleneck event.

It would not take much of a change in human mutation rates and assumptions about population sizes to make the numbers point to a VERY recent date for the arrival of modern humans.  Not a Bishop Usher type date, but not one that is a good fit for human evolution either.

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