Leucistic Texas Rat snake

Numerous spontaneously-occurring color morphs, including xanthic, albino, hypomelanistic, and leucistic, have been recognized in the Texas rat snake. We focused on the leucistic morph, characterised by ivory-white skin coloration and eyes that maintain their pigmentation. Leucistic individuals exist in the wild and they have been independently introduced to the pet trade in different occasions, thus we expect several independant lineages to be bred.

Using a candidate gene approach and our newly assembled Texas Rat snake genome, we suggest that mutations affecting the regulation and, in some cases, the coding sequence of MITF, the former probably predating the latter, could be associated with the leucistic phenotype in Texas rat snakes. Transmission electron microscopy of the Leucistic skin revealed that melanophores and xanthophores are absent and only iridophores persist. We thus propose that fate determination of neural-crest derived melanophores and xanthophores, but not of iridophores, could require the expression of MITF during snake embryonic development.

Associated Publication
Ullate-Agote A. and Tzika A. C.*
“Characterization of the Leucistic Texas Rat Snake Pantherophis obsoletus
Frontiers in Ecology and Evolution (2021) Special issue "Evo-Devo of Color Pattern Formation"

Leucistic Texas Rat snake morph A wild type (left) and a Leucistic (right) Texas Rat snake.