Sorry, I dropped off this thread, but I’m still pretty confused, so I hope you’ll bear with me, but this seems important for a layperson like me to understand.
So mutation rate is really the only assumption used? And is it assumed to be constant, then?
What is the sample size of the verification of mutation rates prior to ~10,000 years ago? Seems like it would be a very small sample size from a limited number of geographic distribution points?
Let me give you an absurd example, and forgive me if this is not the best one… there are probably better examples, but let me try…I’m making this up and realize it’s extreme, but bear with me…
A bottleneck population, Group A, of 100 people exists 20,000 years ago. They have a strict reproductive society, where only a certain, small upper class of people are allowed to reproduce and it is strictly regulated.
After 10,000 years, Group B, a population of 5,000, splits off from A and is isolated. They adopt the extreme opposite of Group A and have a society of “free love,” where everyone has offspring with everyone else.
Perhaps one of these groups, maybe Group B, values diversity, where those who are the most “unique” are more attractive and thus, more likely to reproduce. In Group A, uniformity is more attractive and those with very different features are less likely to reproduce.
In the last 2,500 years, Group A and Group B recombine into Group C, and they adopt the free love society of Group B.
We have genetic samples from Group C and Group B, but none from Group A, so as far as we know, Group A may never have existed?
Edited: Based only on the DNA from samples in Group C and a little from Group B, what bottleneck would we come up with and when?
Again, there are probably better ways to do illustrate my point here, but it seems you could come up with some scenarios like this that would give wildly different bottleneck sizes and ages, based on wildly different genetic mixing rates and mutation rates, right?
Have there been studies that have done this kind of extreme scenario modeling and, if so, what bottleneck sizes and age ranges did those come up with?
Thanks and again, sorry if I’m not explaining this well.
ALSO: Perhaps we can break this off into a new thread, such as “Assumptions used in population bottleneck models.” While I might be a dummy, I guess I object to these questions of mine falling under this heading. =)