Simulating genetic drift

The Wright-Fisher model is about the simplest population-genetic model there is. It consists of:

• A population of N individuals (which stays fixed over time).
• non-overlapping generations
• in each generation, each individual 'samples' its parents uniformly from individuals in the parent generation.

It looks like this:

(TODO figure)

It's pretty simple to implement, but even so it turns out to have many of the key features of real populations. We are going to implement a simplified version, where each individual picks only one parent (as if we were following a single DNA haplotype).

Note that both R and Python are used extensively in genetics so to get you comfortable, this session shows the equivalent code in both. Later we will use Python software such as msprime to perform genetic simulation, so it's worth getting to grips with the differences between the two languages.