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A NEW MODEL FOR EXTINCTION AND RECOLONIZATION IN TWO DIMENSIONS: QUANTIFYING PHYLOGEOGRAPHY
Author(s) -
Barton Nicholas H.,
Kelleher Jerome,
Etheridge Alison M.
Publication year - 2010
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.2010.01019.x
Subject(s) - biology , evolutionary biology , event (particle physics) , gene flow , phylogeography , extinction (optical mineralogy) , population , genetic diversity , genetics , genetic variation , gene , phylogenetics , paleontology , demography , physics , quantum mechanics , sociology
Classical models of gene flow fail in three ways: they cannot explain large‐scale patterns; they predict much more genetic diversity than is observed; and they assume that loosely linked genetic loci evolve independently. We propose a new model that deals with these problems. Extinction events kill some fraction of individuals in a region. These are replaced by offspring from a small number of parents, drawn from the preexisting population. This model of evolution forwards in time corresponds to a backwards model, in which ancestral lineages jump to a new location if they are hit by an event, and may coalesce with other lineages that are hit by the same event. We derive an expression for the identity in allelic state, and show that, over scales much larger than the largest event, this converges to the classical value derived by Wright and Malécot. However, rare events that cover large areas cause low genetic diversity, large‐scale patterns, and correlations in ancestry between unlinked loci.