Figure 3.

Effects of Demographic Parameters on IBD Sharing

When a population of constant size N_e is considered (A), a larger number of individuals in the population results in a decreased chance of sharing IBD segments across all length intervals. A similar behavior is observed for the case of an exponential population expansion (B) parameterized by N_a ancestral individuals exponentially expanding to N_c current individuals during G generations. Larger values of N_a and N_c correspond to a smaller chance of IBD sharing for short and long segments, respectively. For fixed N_a and N_c, changes in G (affecting the expansion rate) have an impact on segments of medium length, i.e., the slope of the distribution between short and long segments.