Experimental Groups.

Adult male and female mice used in this study were; Mc1re, recessive yellow mice, which are null mutants with a non-functional MC1R resulting in a yellow coat colour and their littermate controls Tg-Mc1re, which are recessive yellow mice whose non-functioning MC1R is rescued with human MC1R and have an agouti coat colour. Ay-Jkn1 are agouti signalling protein (ASP) over-expressing mice with a functioning mouse MC1R resulting in a yellow coat colour and their littermate controls, control non-Ay-Jkn1, are mice that do not over-express ASP and have a functioning mouse MC1R and a black coat colour.