Admixture

In this practice we are going to explore the result of creating a population by mixing two distant populations. Let’s imagine that a long time ago the an ancestral population was split in two. In nature this is a common proccess, for instance, it could happen due to a new mountain range. During many generation the two doughter populations, named A and B in our practice, evolve independently, thus accumulating differences. Then, more recently, a new population is created by mixing these differentiated A and B population.

Let’s simmulate this process and explore the effect of on the genetic diversity of this admixture.

Admixture simulation application

Diversity in the admixtured population

How do you think that the expected heterozygosity, the number of polymorphic markers and the number of markers will change in the admixtured population when compared with both parent populations? Run the simulation, find out which is the real behaviour and explain it.

Describe the change in the Allele Frequency Spectrum and explain the result.

Population distances

What is the distance of the admixtured population when compared with the distance between populations A and B?

How do you think that the individual genotypes of the admixtured population will appear in the PCA? Run the simulation several times, observe the behaviour of the PCA and explain the result.