Abstract

Many recent studies have addressed the mechanisms operating during the early stages of speciation, but surprisingly few studies have tested theoretical predictions on the evolution of strong reproductive isolation (RI). To help address this gap, we first undertook a quantitative review of the hybrid zone literature for flowering plants in relation to reproductive barriers. Then, using Populus as an exemplary model group, we analysed genome-wide variation for phylogenetic tree topologies in both early- and late-stage speciation taxa to determine how these patterns may be related to the genomic architecture of RI. Our plant literature survey revealed variation in barrier complexity and an association between barrier number and introgressive gene flow. Focusing on Populus, our genome-wide analysis of tree topologies in speciating poplar taxa points to unusually complex genomic architectures of RI, consistent with earlier genome-wide association studies. These architectures appear to facilitate the 'escape' of introgressed genome segments from polygenic barriers even with strong RI, thus affecting their relationships with recombination rates. Placed within the context of the broader literature, our data illustrate how phylogenomic approaches hold great promise for addressing the evolution and temporary breakdown of RI during late stages of speciation. This article is part of the theme issue 'Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers'.

Keywords

speciation; hybridization; reproductive isolation; gene flow; topology discordance; recombination rate

Published in

Philosophical Transactions B: Biological Sciences
2020, Volume: 375, number: 1806, article number: 20190544
Publisher: ROYAL SOC

SLU Authors

• Ingvarsson, Pär

  • Department of Plant Biology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Evolutionary Biology
Botany


Publication identifier

DOI: https://doi.org/10.1098/rstb.2019.0544

Permanent link to this page (URI)

https://res.slu.se/id/publ/107157