solution

Populations are often modeled as consisting of genes without reference to individuals or gender. This abstract model of a population is called the Wright–Fisher model in honor of two founding figures of population genetics, Ronald A. Fisher (1890–1962) and Sewall Wright (1889–1988). Figure 6.4 shows two generations in the evolution of a Wright–Fisher population. To get from one generation to the next, ancestors are simply picked at random, as indicated by the arrows. To see how this works, extend Fig. 6.4 for one generation by manually drawing another set of eight genes in g3. To determine the ancestor of the first gene, use

and draw the appropriate arrow. Then repeat for the remaining genes.