Other Talks in the Series: Human Population Genetics II

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Hello, my name is Paul Verdu. I am a tenured researcher at the CNRS hosted at the Museum of Mankind in Paris, France, and today I am going to talk to you about human admixture.
[Genetic admixture processes: a population genetics perspective] We will first investigate genetic admixture processes from a theoretical and a population genetics perspective. Then, we will talk and investigate human admixture as a phenomenon through isolation, migration, and in particular, sociocultural behavior. Finally, we will illustrate these points with the case study of genetic admixture between "Pygmy" and "non-Pygmy" populations from Central Africa.
Genetic admixture processes: a population genetics perspective.
What is genetic admixture? Admixture between populations can be classically defined as exchanges of genes between two or more previously reproductively isolated populations. In this cartoon, you can see population one and population two, which we will call source populations. They are isolated, but at some point in time— time, T here— they send migrants, or genes, with proportion s1 and s2 in this cartoon, with s1 plus s2 equals one, to form a third population that we'll denote as admixed. In particular, admixed individuals have a fraction of their genome, denoted H, that is derived from the gene pool of one of the previously isolated source populations. Be careful here—admixed individuals, per se, are individuals who have a fraction of their genome coming from each one of the source populations, so H for the admixed individual is between zero and one. The admixed population, per se, can withhold individuals that are not genetically admixed but that are just migrants from the first or the second source population.