Multispecies Coalescent
MULTISPECIES COALESCENT. Acer palmatum, Japanese maple.
Cottrell Way.
The multispecies coalescent is a model in which a tree of species relationships is treated as fixed, and the descent of genetic lineages is constrained by the species relationships. At each node of the species tree, a genetic lineage, representing a specific individual in the species, travels along a specific branch of the species tree. The genetic lineages produce a “gene tree,” which may or may not have the same branching relationships as the species tree. The multispecies coalescent model describes the probabilities of outcomes for random gene trees constrained by a specific species tree.
The Japanese maple here is the “species tree,” and the lights represent descent from one generation to the next in the “gene tree” (see Rosenberg et al. 2002 Nature Rev Genet 3:380-390 , Box 1).
Photo: Noah Rosenberg, April 15, 2020