Human population growth and its impact on genetic variation

Published on April 21, 2015   34 min

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Other Talks in the Series: Human Population Genetics II

Hi, my name is Andy Clark, and I would like to tell you about the human population growth and its impact on genetic variation.
We're going to begin with some simple population genetics to get an idea of what we expect to be the behavior of genetic variation in a population of different sizes. First we're going to start with a particular model called an infinite alleles model, and this model describes the balance between the input of genetic variation by mutation, and the loss of that variation by random genetic drift. This model predicts that the amount of heterozygosity, H in the population at equilibrium will be theta divided by theta plus one. I'll spare you the derivation of that, but this is an essential conclusion from this infinite alleles model. Theta is the population mutation rate, and theta is equal to four times the effective population size times the mutation rate. I'll be talking a little bit more about what that term "effective population size" is in just a moment. As I mentioned, H is the heterozygosity of the population or the probability that when you draw two copies of a gene, they will be different from each other in a sample from that population.

Human population growth and its impact on genetic variation

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