....¹

I hope that's beginning to sound familiar by now.

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... generation.²

An important assumption of the coalescent is that populations are large enough that we can ignore the possibility that there is more than one coalescent event in a single generation. We also only allow coalescence between a pair of alleles, not three or more. In both ways the mathematical model of the process differs from the diagram in Figure 1.

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... is,³

How many times have you seen this now? The only complication is that I'm specifying that we're interested in the inbreeding effective size.

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... that.⁴

Remember that we're counting generations backward in time, so when I say that a coalescent event occurred at time $t$ I mean that it occurred $t$ generations ago.

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....⁵

If you've had a little bit of probability theory, you'll notice that equation 1 shows that the coalescence time is a geometric random variable.

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... alleles.⁶

Okay, okay. What I should really have said is ``It's not too hard to extend this approach to multiple alleles.`q''

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... follows⁷

Using logic just like what we used in the two allele case.

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... is⁸

If you don't see why, don't worry about it. You can ask if you really care. We only care about $\bar t$ for what follows anyway.

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... progress.⁹

Well, we can't make any more progress using $F$-statistics. We'll see in the last week or two of the course that it is possible to make some progress on disentangling the relative role of migration and common ancestry by using more of the information available in molecular data.

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