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Isolation and reconnection: Demographic history and multiple contact zones of the green odorous frog ( Odorrana margaretae ) around the Sichuan Basin
Author(s) -
Wen Guannan,
Fu Jinzhong
Publication year - 2021
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.16021
Subject(s) - biology , introgression , hybrid zone , reproductive isolation , ecology , demographic history , genetic divergence , population , zoology , gene flow , evolutionary biology , genetic variation , genetics , genetic diversity , demography , sociology , gene
The green odorous frog ( Odorrana margaretae ) displays a circular distribution around the Sichuan Basin of western China and possesses multiple replicate hybrid zones between lineages with high levels of divergence. To gain an understanding of the speciation process, we obtained 1540 SNPs from 29 populations and 227 individuals using ddRAD sequencing. Population structure analysis revealed three groups within the species: the West, North & South, and East groups. Demographic inference showed that they were initially isolated at ~2 million years ago, and subsequent post‐glacial expansion produced the current circular distribution with four secondary contact zones. Hybridization in those zones involved lineages with various levels of divergence and produced greatly different patterns of introgression. Contact zones between the East and North & South groups (E–S and E–N) had contrast admixture levels but both showed a general lack of potential barrier loci. Meanwhile, the reconnection of the West and North & South groups produced two contact zones along the rim of the Basin. The S–W zone had extensive admixture while the N–W zone had limited admixture within a narrow geographic distance. Both showed substantial barrier effects, and a large number of potential barrier loci were shared. We also detected strong coupling among these loci. The N–W hybrid zone involved two highly‐diverged lineages ( F ST = 0.704) and many loci have reached fixation around the hybrid zone. This study system offers a unique opportunity to understand the dynamics of introgression in contact zones and the architecture of reproductive isolation at different stages of speciation.