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Widespread hybridization and bidirectional introgression in sympatric species of coral reef fish
Author(s) -
Harrison Hugo B.,
Berumen Michael L.,
SaenzAgudelo Pablo,
Salas Eva,
Williamson David H.,
Jones Geoffrey P.
Publication year - 2017
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.14279
Subject(s) - introgression , biology , sympatric speciation , coral reef fish , coral reef , pomacentridae , ecology , hybrid , evolutionary biology , genetics , gene , botany
Coral reefs are highly diverse ecosystems, where numerous closely related species often coexist. How new species arise and are maintained in these high geneflow environments have been long‐standing conundrums. Hybridization and patterns of introgression between sympatric species provide a unique insight into the mechanisms of speciation and the maintenance of species boundaries. In this study, we investigate the extent of hybridization between two closely related species of coral reef fish: the common coral trout ( Plectropomus leopardus ) and the bar‐cheek coral trout ( Plectropomus maculatus ). Using a complementary set of 25 microsatellite loci, we distinguish pure genotype classes from first‐ and later‐generation hybrids, identifying 124 interspecific hybrids from a collection of 2,991 coral trout sampled in inshore and mid‐shelf reefs of the southern Great Barrier Reef. Hybrids were ubiquitous among reefs, fertile and spanned multiple generations suggesting both ecological and evolutionary processes are acting to maintain species barriers. We elaborate on these finding to investigate the extent of genomic introgression and admixture from 2,271 SNP loci recovered from a dd RAD library of pure and hybrid individuals. An analysis of genomic clines on recovered loci indicates that 261 SNP loci deviate from a model of neutral introgression, of which 132 indicate a pattern of introgression consistent with selection favouring both hybrid and parental genotypes. Our findings indicate genome‐wide, bidirectional introgression between two sympatric species of coral reef fishes and provide further support to a growing body of evidence for the role of hybridization in the evolution of coral reef fishes.