Linking patterns of genetic variation to processes of diversification in Malaysian torrent frogs (Anura: Ranidae: Amolops): a landscape genomics approach

Abstract

The interplay between environmental attributes and evolutionary processes can provide valuable insights into how biodiversity is generated, partitioned, and distributed. This study investigates the role of spatial, environmental, and historical factors that could potentially drive diversification and shape genetic variation in Malaysian torrent frogs. Torrent frogs are ecologically conserved, and we hypothesize that this could impose tight constraints on dispersal routes, gene flow, and consequently genetic structure. Moreover, levels of gene flow were shown to vary among populations from separate mountain ranges, indicating that genetic differentiation could be influenced by landscape features. Using genome-wide SNPs in conjunction with landscape variables derived from GIS, we performed distance-based redundancy analyses and variance partitioning to disentangle the effects of isolation-by-distance (IBD), isolation-by-environment (IBE), and isolation-by-colonization (IBC). Our results demonstrated that IBE, contributed minimally to genetic variation. Intraspecific population structure can be largely attributed to IBD, whereas interspecific diversification was primarily driven by IBC. We also detected two distinct population bottlenecks, indicating that speciation events were likely driven by vicariance or founder events.