Hybridization patterns reveal spatial variation in reproductive isolation between two closely related abalone species
Empirical studies demonstrating ecological speciation in marine invertebrates are limited. Two large abalone species, Haliotis discus discus and H. madaka, in the Japanese archipelago are considered to be involved in this process. Previous population genomic studies have indicated that hybridization between these two species continues because of incomplete reproductive isolation. However, owing to the limited number of samples in the previous study, the nature of hybridization remains unclear. In this study, we performed population genomic analyses of these two species using samples from multiple geographical regions.