Functional characterization of Mc1r in Xenopus tropicalis
This study investigates the previously unexplored role of melanocortin 1 receptor (Mc1r) in amphibian pigmentation using CRISPR-mediated knockout in Xenopus tropicalis. We demonstrate that mc1r ablation disrupts dorsal-ventral pigmentation patterning, reducing dorsal skin pigmentation while accelerating ventral melanophore differentiation, ultimately impairing the species' evolutionary conserved countershading. Transcriptomic analyses further reveal dysregulation of pigmentation-associated gene networks. These findings establish MC1R as a critical regulator of amphibian pigmentation and countershading morphogenesis, expanding our understanding of MC1R's functional evolution across vertebrates.