10.5061/DRYAD.TB2RBNZWJ
Hamlin, Jennafer
0000-0001-7037-134X
University of Georgia
Hibbins, Mark
0000-0002-4651-3704
Indiana University Bloomington
Moyle, Leonie
Indiana University Bloomington
Data from: Assessing biological factors affecting post-speciation introgression
Dryad
dataset
2019
whole genome
Mating Systems
2020-02-25T00:00:00Z
2020-02-25T00:00:00Z
en
4501997183 bytes
8
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
An increasing number of phylogenomic studies have documented a
clear ‘footprint’ of post-speciation introgression
among closely-related species. Nonetheless, systematic genome-wide studies
of factors that determine the likelihood of introgression remain rare.
Here, we propose an a priori hypothesis-testing framework that uses
introgression statistics—including a new metric of
estimated introgression, Dp —to evaluate general patterns of introgression
prevalence and direction across multiple closely related species. We
demonstrate this approach using whole genome sequences from 32 lineages in
11 wild tomato species to assess the effect of three factors on
introgression—genetic relatedness, geographical proximity, and mating
system differences—based on multiple trios using the ‘ABBA-BABA’ test. Our
analyses suggest each factor affects the prevalence of introgression,
although our power to detect these is limited by the number of comparisons
currently available. We find that of 14 species pairs with
geographically ‘proximate’ versus ‘distant’ population comparisons, 13
showed evidence of introgression; in ten of these cases, this was more
prevalent between geographically-closer populations. We also find
modest evidence that introgression declines with increasing genetic
divergence between lineages, is more prevalent between lineages that share
the same mating system, and—when it does occur between mating
systems—tends to involve gene flow from more inbreeding to more
outbreeding lineages. While our analysis indicates that recent
post-speciation introgression is frequent in this group—detected in 15 of
17 tested trios—estimated levels of genetic exchange are modest (0.2-2.5%
of the genome), so the relative importance of hybridization in shaping the
evolutionary trajectories of these species could be limited. Regardless,
similar clade-wide analyses of genomic introgression would be valuable for
disentangling the major ecological, reproductive, and historical
determinants of post-speciation gene flow, and for assessing the
relative contribution of introgression as a source of genetic variation