Inbred strains of Xenopus tropicalis show morphological and genetic variation.

The emergence of individuality and morphological divergence within a population is crucial for evolutionary potential. This study investigated genetic and phenotypic variation among four inbred strains of Xenopus tropicalis, a promising model amphibian species. We examined four inbred lineages derived from source populations in Nigeria and Côte d'Ivoire, focusing specifically on phenotypic diversity in the absence of environmental influences. Through comprehensive morphological assessments-including body size measurements, mating calls, and coloration-we identified significant differences between sexes and among strains, with pronounced variations in body size, coloration, and claw morphology. In particular, acoustic traits differed between Nigerian-derived strains and the Côte d'Ivoire-derived strain. These findings indicate that inbred strains of X. tropicalis retain measurable phenotypic divergence under controlled rearing conditions. This study underscores the rich genetic and morphological variation retained among inbred strains, highlighting their value for studying phenotypic divergence and evolutionary potential. This strain panel therefore provides a useful resource for future studies of the genetic and developmental mechanisms underlying phenotypic variation in amphibians.