In mammals the melanocortin 4 receptor (Mc4r) signaling system has been mainly associated with the regulation of appetite and energy homeostasis. In fish of the genus Xiphophorus (platyfish and swordtails) puberty onset is genetically determined by a single locus. which encodes the mc4r. Wild populations of Xiphophorus are polymorphic for early and late-maturing individuals. https://unionlosangelers.shop/product-category/jackets/