[Physicist]

The key question, though, is where and when the evolutionary bottleneck occured. Any model of geographically separated but commingling populations has to be consistent with the genetic data, which has been interpreted in terms of a very small number of humans, and a single maternal ancestor, at some time in the period 50,000 - 100,000 B.C..

But a single common ancestor (e.g., a "mitochondrial Eve") doesn't necessarily imply a genetic bottleneck. It's possible that a (mutant) woman was born with significantly superior mitochondria, which slowly over time supplanted the other mitochondria throughout a large and sustained population with an otherwise diverse gene pool, without the need for a mass die-off, or for one population pushing out another. (This could similarly work for any given chromosome.)

[Tallguy]

It's possible that a (mutant) woman was born with significantly superior mitochondria, which slowly over time supplanted the other mitochondria throughout a large and sustained population with an otherwise diverse gene pool, without the need for a mass die-off, or for one population pushing out another.

That's pretty much the way it was explained to me. In fact, all such genetic studies are essentially statistical samples. The fact that they haven't found another set of mitocondrial genes from a second "Eve", doesn't mean that she didn't exist. It's just that the statistical chances that there is modern evidence of a second "Eve" are diminishing to the Zero Point.