Genetic factors implied in melanin-based coloration of the Italian wall lizard

As largely demonstrated for a wide range of vertebrates, the melanin-based coloration can be the effect of both mutations in the melanocortin-1 receptor (MC1R) gene and of differential expression of the same gene. However, in lizards, this mechanism is poorly known and some populations exhibit a high variation of melanism. Some populations of Podarcis siculus show a gradual melanization, suggesting a case of a quantitative phenomenon rather than a qualitative one. Here, we objectively quantify the continuous colour variation by spectrophotometric analysis demonstrating that the changes in the skin reflectance are not associated to mutations in the coding region of the MC1R gene but seem to be related to a concomitant variation of expression for this gene.