Genealogical asymmetry under the IM model and a two-taxon test for gene flow.

ABSTRACT: Methods for detecting gene flow between populations often rely on asymmetry in the average length of particular genealogical branches, with the ABBA-BABA test being a well known example. Currently, asymmetry-based methods cannot be applied to a pair of populations and such analyses are instead performed using model-based methods. Here we investigate genealogical asymmetry under a two-population Isolation with Migration model. We focus on genealogies where the first coalescence event is between lineages sampled from different populations, as the external branches of these genealogies have equal expected length as long as there is no post-divergence gene flow. We show that unidirectional gene flow breaks this symmetry and results in the recipient population having longer external branches. W

SUBMITTER: Mackintosh A 

PROVIDER: S-EPMC11631468 | biostudies-literature | 2024 Sep

REPOSITORIES: biostudies-literature