title: Amelanism in the corn snake is associated with the insertion of an LTR-retrotransposon in the OCA2 gene.
abstract: The corn snake (Pantherophis guttatus) is a new model species particularly appropriate for investigating the processes generating colours in reptiles because numerous colour and pattern mutants have been isolated in the last five decades. Using our captive-bred colony of corn snakes, transcriptomic and genomic next-generation sequencing, exome assembly, and genotyping of SNPs in multiple families, we delimit the genomic interval bearing the causal mutation of amelanism, the oldest colour variant observed in that species. Proceeding with sequencing the candidate gene OCA2 in the uncovered genomic interval, we identify that the insertion of an LTR-retrotransposon in its 11(th) intron results in a considerable truncation of the p protein and likely constitutes the causal mutation of amelanism in corn snakes. As amelanistic snakes exhibit white, instead of black, borders around an otherwise normal pattern of dorsal orange saddles and lateral blotches, our results indicate that melanocytes lacking melanin are able to participate to the normal patterning of other colours in the skin. In combination with research in the zebrafish, this work opens the perspective of using corn snake colour and pattern variants to investigate the generative processes of skin colour patterning shared among major vertebrate lineages.
authors.affiliation: Laboratory of Artificial &Natural Evolution (LANE), Department of Genetics &Evolution, University of Geneva, Switzerland.
authors.forename: Suzanne V
authors.initials: SV
authors.lastname: Saenko
authors.affiliation: Science of Life Laboratory Uppsala, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
authors.forename: Sangeet
authors.initials: S
authors.lastname: Lamichhaney
authors.affiliation: Science of Life Laboratory Uppsala, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Martinez Barrio
authors.affiliation: Science of Life Laboratory Uppsala, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
authors.forename: Nima
authors.initials: N
authors.lastname: Rafati
authors.affiliation: Science of Life Laboratory Uppsala, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.|Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.|Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, USA.
authors.forename: Leif
authors.initials: L
authors.lastname: Andersson
authors.affiliation: Laboratory of Artificial &Natural Evolution (LANE), Department of Genetics &Evolution, University of Geneva, Switzerland.|SIB Swiss Institute of Bioinformatics, Geneva, Switzerland.
authors.forename: Michel C
authors.initials: MC
authors.lastname: Milinkovitch
mesh_terms: D000818:Animals; D017812:Colubridae / Q000235:genetics* / Q000378:metabolism; D008543:Melanins / Q000378:metabolism; D016254:Mutagenesis, Insertional; D030162:Reptilian Proteins / Q000235:genetics*; D018626:Retroelements; D017422:Sequence Analysis, DNA; D012880:Skin Pigmentation
chemical_list: D008543:Melanins; D030162:Reptilian Proteins; D018626:Retroelements