Figure 1.—

Gene genealogies of a sample of two completely linked loci (a) from a population that has recently grown in size and (b) from a stable population. One mutation event is assumed at each locus, and the ancestral gametic type is AB. The sample in a consists of one each of aB and Ab, and four AB, indicating low linkage disequilibrium. The sample in b consists of the gametic types aB and Ab in equal proportions, indicating high linkage disequilibrium.