Inference Methods for Multiple Merger Coalescents

Abstract

Some populations, including a diverse group of marine populations such as Pacific oysters and Atlantic cod, are highly fecund. Models of high fecundity—coupled with a skewed offspring distribution—have coalescent processes, which admit (simultaneous) multiple mergers of ancestral lineages associated with them. In contrast, the celebrated and extensively employed Kingman’s coalescent only admits pairwise mergers of ancestral lineages. We review multiple merger coalescent models derived from population models, which admit high fecundity and skewed offspring distribution. Inference methods that have been developed based on these multiple merger coalescent models will also be reviewed. In fact, multiple merger coalescent models are able to predict the excess singletons (relative to Kingman’s coalescent predictions) observed in the commercially important Atlantic cod. These models may be applicable to a wide range of natural populations—including a diverse group of marine organisms, viruses, and plants which distribute seeds—with significant implications.