TY - JOUR

T1 - Genome-wide patterns of divergence and introgression after secondary contact between Pungitius sticklebacks

AU - Yamasaki, Yo Y.

AU - Kakioka, Ryo

AU - Takahashi, Hiroshi

AU - Toyoda, Atsushi

AU - Nagano, Atsushi J.

AU - Machida, Yoshiyasu

AU - Møller, Peter Rask

AU - Kitano, Jun

PY - 2020

Y1 - 2020

N2 - Speciation is a continuous process. Although it is known that differentialadaptation can initiate divergence even in the face of gene flow, we knowrelatively little about the mechanisms driving complete reproductive isolation and the genomic patterns of divergence and introgression at thelater stages of speciation. Sticklebacks contain many pairs of sympatricspecies differing in levels of reproductive isolation and divergence history.Nevertheless, most previous studies have focused on young species pairs.Here, we investigated two sympatric stickleback species, Pungitius pungitiusand P. sinensis, whose habitats overlap in eastern Hokkaido; these speciesshow hybrid male sterility, suggesting that they may be at a late stage ofspeciation. Our demographic analysis using whole-genome sequence datashowed that these species split 1.73 Ma and came into secondary contact37 200 years ago after a period of allopatry. This long period of allopatrymight have promoted the evolution of intrinsic incompatibility. Althoughwe detected on-going gene flow and signatures of introgression, overallgenomic divergence was high, with considerable heterogeneity across thegenome. The heterogeneity was significantly associated with variation inrecombination rate. This sympatric pair provides new avenues to investigatethe late stages of the stickleback speciation continuum.This article is part of the theme issue ‘Towards the completion ofspeciation: the evolution of reproductive isolation beyond the first barriers’.

AB - Speciation is a continuous process. Although it is known that differentialadaptation can initiate divergence even in the face of gene flow, we knowrelatively little about the mechanisms driving complete reproductive isolation and the genomic patterns of divergence and introgression at thelater stages of speciation. Sticklebacks contain many pairs of sympatricspecies differing in levels of reproductive isolation and divergence history.Nevertheless, most previous studies have focused on young species pairs.Here, we investigated two sympatric stickleback species, Pungitius pungitiusand P. sinensis, whose habitats overlap in eastern Hokkaido; these speciesshow hybrid male sterility, suggesting that they may be at a late stage ofspeciation. Our demographic analysis using whole-genome sequence datashowed that these species split 1.73 Ma and came into secondary contact37 200 years ago after a period of allopatry. This long period of allopatrymight have promoted the evolution of intrinsic incompatibility. Althoughwe detected on-going gene flow and signatures of introgression, overallgenomic divergence was high, with considerable heterogeneity across thegenome. The heterogeneity was significantly associated with variation inrecombination rate. This sympatric pair provides new avenues to investigatethe late stages of the stickleback speciation continuum.This article is part of the theme issue ‘Towards the completion ofspeciation: the evolution of reproductive isolation beyond the first barriers’.

U2 - 10.1098/rstb.2019.0548

DO - 10.1098/rstb.2019.0548

M3 - Journal article

C2 - 32654635

VL - 375

JO - Philosophical Transactions of the Royal Society B: Biological Sciences

JF - Philosophical Transactions of the Royal Society B: Biological Sciences

SN - 0962-8436

IS - 1806

M1 - 20190548

ER -