Genetic basis of coat colour variation in members of genus Panthera

Coat colouration in mammals depends upon the quantity, quality and distribution of melanin in the body, which is produced through a complicated and tightly regulated metabolic pathway operating in the melanosomes of mammalian melanocytes. The branches of this pathway produce two pigments, namely eumelanin and pheomelanin, the ratio of which determines the colour appearance. Loss-of-function and/or gain-of-function mutations in the genes encoding enzymes, receptors, and signals involved in this pathway alter the amount of pigment(s) produced, contributing to the diversity of hair colours/patterns observed. Furthermore, the variety is enhanced by changes in the genetic control of melanocyte differentiation, melanoblast migration and melanin transportation. This phenomenon of variability in colour coat pattern is well characterized in domestic and wild cats, therefore this literature review aims to concatenate the fragmented information available on the genetic analysis of coat colour polymorphism in big cats of the genus Panthera, namely the tiger, lion, jaguar, leopard, and snow leopard, simultaneously underscoring the adaptive significance of such polymorphic colour coats.