Hierarchical population genetic structure and signatures of adaptation in Lates calcarifer

ContextLates calcarifer is a widespread Indo-Pacific fish that is important in aquaculture, recreational and commercial fisheries. Genetic divergences from different data sources and sampling schemes have been reported. AimsTo conduct phylogenetic and population genetic analyses from a geographically and phylogenetically representative data set to identify hierarchical divisions within L. calcarifer. We further test the evolutionary significance of genetic units in terms of signatures of adaptation. MethodsUsing a whole-genome sequence data set of 61 fish including an outgroup, we conducted phylogenetic and population genetic analyes. We also generated measures of Fst, nucleotide diversity ({pi}) and Tajimas D (D). Key ResultsWe identify three main lineages of L. calcarifer corresponding to the Indian subcontinent, Southeast Asia and Australasia. Subdivision within each of the three main lineages is also identified and characterized. Adaptively significant differences are indicated within and between the three main lineages. ConclusionsL. calcarifer exhibits genetic divergences at different levels that originate before and during the Pleistocene. These divergences are associated with adaptive divergence but unclear phenotypic changes. ImplicationsThis study highlights the need for comprehensive sampling and integrative study of genotypes and phenotypes across the range of L. calcarifer.