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70,000 years ago, Homo sapiens sapiens suffered a genetic bottleneck that reduced the population of likely 100,000 to 3,000. Over seven billion people of several distinctive races are descended from those small survivors. Whether or not the supereruption of Toba was to blame is still under debate.

My question is, though, if the bottleneck never happened or was at least delayed, would humankind's racial diversity be greater? If so, through what characteristics?

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  • $\begingroup$ That seems like two totally different scenarios. Never happened means greater diversity, while delayed but still before now means less diversity. $\endgroup$ – Samuel Jun 14 '15 at 4:49
  • $\begingroup$ If the bottleneck never occurred, then there would certainly be more genetic diversity, though it is not clear if this would necessarily imply (greatly) more racial diversity. If the bottleneck was delayed, then we would "start again" from a lower base of diversity and lag our current genetic diversity. One assumes that a delayed bottleneck may give rise to different paths for mutations because of different environmental factors. $\endgroup$ – Nick Jun 14 '15 at 4:56
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Well, surprisingly it probably wouldn't be that much difference in the genetics. There are likely a few traits that we lost from the others that died, but with a little math, 3000 individuals at a .1% growth rate (1 more child per 1000 survives than total deaths a year avg.) it would take ~3500 years for the population to recover to 100,000. That is not a lot of time for diversity changes in a population. The biggest difference is we would likely be a couple thousand years farther advanced technologically, being pushed by a much larger population much earlier.

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    $\begingroup$ On the other hand, a smaller population might put evolutionary pressure on the remaining population in the direction of further advancement. Or it might remove aspects that hinder progress. As just one example, if the population suddenly drops by 97% then lots of territory becomes available which was previously occupied, meaning within the territory of any one group there is potentially more to eat as well as less risk of intraspecific conflict. I think it would be hard to say generally what the long-term effects of such a population drop at a given time would be. $\endgroup$ – a CVn Jun 14 '15 at 13:25

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