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Candidate genes underlying hypomelanistic morphs in squamate reptiles
Pierre Beaudier1, Asier Ullate-Agote1, Athanasia C Tzika1
1Laboratory of Artificial and Natural Evolution, Department of Genetics and Evolution, University of Geneva, Geneva 1205, Switzerland.
Genetics
|November 3, 2025
Summary
Investigating hypomelanistic traits in snakes and lizards reveals mutations in key pigment genes like tyrosinase (TYR) and NCKX5. This highlights conserved genetic pathways and species-specific effects in vertebrate skin coloration.
Area of Science:
- * Genetics and developmental biology
- * Comparative genomics and molecular evolution
- * Vertebrate pigmentation and cell biology
Background:
- * Skin coloration is vital for animal survival, with melanophores controlling melanin production for camouflage and display.
- * Hypomelanistic and amelanistic phenotypes, common in mammals, are less understood in reptiles like snakes and lizards.
- * Understanding the genetic basis of these color morphs can reveal insights into conserved pigmentation pathways.
Purpose of the Study:
- * To genetically and histologically characterize hypomelanistic corn snake and leopard gecko morphs.
- * To identify candidate genes involved in reptile pigmentation and melanogenesis.
- * To explore the evolutionary flexibility and species-specific effects of pigmentation genes.
Main Methods:
- * Chromosome-level genome assembly of a wild-type leopard gecko.
- * Genomic, transcriptomic (bulk RNA sequencing), and histological analyses of mutant morphs.
- * Electron microscopy to examine melanophore subcellular structure.
Main Results:
- * Identified candidate mutations in melanogenesis factors: tyrosinase (TYR), NCKX5 (SLC24A5), and P protein (OCA2).
- * Detected dysregulation of additional pigmentation genes affecting melanin production, melanosome motility, and melanophore migration in mutant embryos.
- * Observed unique alterations in melanophore subcellular structure across the four studied morphs, suggesting multigenic effects.
Conclusions:
- * Conserved pigmentation genes can yield species-specific effects, demonstrating the modularity of skin coloration.
- * Reptiles serve as valuable comparative models for studying pigment cell biology.
- * The genetic regulation of melanogenesis shows significant evolutionary flexibility across vertebrates.
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