Gene Flow and Habitat Heterogeneity Shape Coexistence Dynamics of Arctic Charr Morphs in Connected Lakes.

ABSTRACT: Sympatric morphs provide valuable systems for studying incipient divergence despite incomplete reproductive isolation. In connected waterbodies with spatially heterogeneous habitats, one or more morphs may form metapopulation structures, generating eco-evolutionary dynamics unlike those in single lakes. We studied the phenotypic and genome-wide differentiation in Arctic charr (Salvelinus alpinus) in two Icelandic lakes: Thingvallavatn, known to harbour four distinct morphs, and a smaller downstream lake, Ulfljotsvatn. Our analyses confirm a single origin of charr polymorphism in this system, with all morphs present in both lakes. Relative morph abundances differ between the lakes: PL-charr dominate in Thingvallavatn, whereas LB-charr are most abundant in Ulfljotsvatn. Three morphs, large-

SUBMITTER: Xiao H 

PROVIDER: S-EPMC12809625 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature