Characterization of the Leucistic Texas Rat Snake Pantherophis obsoletus

Albinism and leucism are phenotypes resulting from impaired melanin pigmentation in the skin appendages. However, of eyes remains unaffected leucism. Here, using transmission electron microscopy, we show that leucistic morph Texas rat snake ( Pantherophis obsoletus lindheimeri ) lacks both melanophores xanthophores its exhibits a uniform ivory white color generated by iridophores collagen fibers. In addition, sequenced full genome individual obtained highly-contiguous near-chromosome quality assembly 1.69 Gb with an N50 14.5 Mb L50 29 sequences. Using candidate-gene approach, then identify single-nucleotide deletion generates frameshift premature termination codon melanocyte inducing transcription factor MITF gene. This mutation shortens translated protein 574 to 286 amino acids, removing helix-loop-helix DNA-binding domain is highly conserved among vertebrates. Genotyping animals independent lineages showed not all individuals carry this deletion. Subsequent gene expression analyses reveal analyzed exhibit significantly decreased MITF. We thus suggest mutations affecting regulation and, some cases, coding sequence , former probably predating latter, could be associated phenotype snakes. involved development survival zebrafish, classical model species for undergoes metamorphosis, larvae adults homozygous mitfa mutants lack melanophores, excess reduced yellow pigmentation. On contrary, snake, non-metamorphic species, only persist. Our results fate determination neural-crest derived xanthophores, but iridophores, require during embryonic development.