TY - JOUR
T1 - Approximate Bayesian Computation Untangles Signatures of Contemporary and Historical Hybridization between Two Endangered Species
AU - Dittberner, Hannes
AU - Tellier, Aurelien
AU - De Meaux, Juliette
N1 - Publisher Copyright:
© 2022 The Author(s) 2022. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
PY - 2022/2/1
Y1 - 2022/2/1
N2 - Contemporary gene flow, when resumed after a period of isolation, can have crucial consequences for endangered species, as it can both increase the supply of adaptive alleles and erode local adaptation. Determining the history of gene flow and thus the importance of contemporary hybridization, however, is notoriously difficult. Here, we focus on two endangered plant species, Arabis nemorensis and A. sagittata, which hybridize naturally in a sympatric population located on the banks of the Rhine. Using reduced genome sequencing, we determined the phylogeography of the two taxa but report only a unique sympatric population. Molecular variation in chloroplast DNA indicated that A. sagittata is the principal receiver of gene flow. Applying classical D-statistics and its derivatives to whole-genome data of 35 accessions, we detect gene flow not only in the sympatric population but also among allopatric populations. Using an Approximate Bayesian computation approach, we identify the model that best describes the history of gene flow between these taxa. This model shows that low levels of gene flow have persisted long after speciation. Around 10 000 years ago, gene flow stopped and a period of complete isolation began. Eventually, a hotspot of contemporary hybridization was formed in the unique sympatric population. Occasional sympatry may have helped protect these lineages from extinction in spite of their extremely low diversity.
AB - Contemporary gene flow, when resumed after a period of isolation, can have crucial consequences for endangered species, as it can both increase the supply of adaptive alleles and erode local adaptation. Determining the history of gene flow and thus the importance of contemporary hybridization, however, is notoriously difficult. Here, we focus on two endangered plant species, Arabis nemorensis and A. sagittata, which hybridize naturally in a sympatric population located on the banks of the Rhine. Using reduced genome sequencing, we determined the phylogeography of the two taxa but report only a unique sympatric population. Molecular variation in chloroplast DNA indicated that A. sagittata is the principal receiver of gene flow. Applying classical D-statistics and its derivatives to whole-genome data of 35 accessions, we detect gene flow not only in the sympatric population but also among allopatric populations. Using an Approximate Bayesian computation approach, we identify the model that best describes the history of gene flow between these taxa. This model shows that low levels of gene flow have persisted long after speciation. Around 10 000 years ago, gene flow stopped and a period of complete isolation began. Eventually, a hotspot of contemporary hybridization was formed in the unique sympatric population. Occasional sympatry may have helped protect these lineages from extinction in spite of their extremely low diversity.
KW - Arabis nemorensis
KW - Arabis sagittata
KW - approximate Bayesian computation
KW - endangered species
KW - hybridization
KW - introgression
UR - http://www.scopus.com/inward/record.url?scp=85124441812&partnerID=8YFLogxK
U2 - 10.1093/molbev/msac015
DO - 10.1093/molbev/msac015
M3 - Article
C2 - 35084503
AN - SCOPUS:85124441812
SN - 0737-4038
VL - 39
JO - Molecular Biology and Evolution
JF - Molecular Biology and Evolution
IS - 2
M1 - msac015
ER -