Alternating patches of black and yellow pigment are a ubiquitous feature of mammalian color variation that contributes to camouflage, species recognition, and morphologic diversity. X-linked determinants of this pattern—recognized by variegation in females but not in males—have been described in the domestic cat as Orange , and in the Syrian hamster as Sex-linked yellow Sly , but are curiously absent from other vertebrate species. Using a comparative genomic approach, we develop molecular markers and a linkage map for the euchromatic region of the Syrian hamster X chromosome that places Sly in a region homologous to the centromere-proximal region of human Xp. Comparison to analogous work carried out for Orange in domestic cats indicates, surprisingly, that the cat and hamster mutations lie in nonhomologous regions of the X chromosome. We also identify the molecular cause of recessively inherited black coat color in hamsters historically referred to as nonagouti as a CysTyr mutation in the Agouti gene. Animals doubly mutant for Sly and nonagouti exhibit a Sly phenotype. Our results indicate that Sly represents a melanocortin pathway component that acts similarly to, but is genetically distinct from, Mc1r and that has implications for understanding both the evolutionary history and the mutational mechanisms of pigment-type switching. THE genetics of coat color is a longstanding and rich model system for studying gene action and cell signaling. Like classical genetic systems in invertebrate model organisms, the cell types and tissues that give rise to mammalian hair color are well characterized and experimentally accessible, and alterations in gene activity can be easily detected.
MATERIALS AND METHODS
Xhamster asian photo desi. Hclips desi masturbation. Pornhub celebrity bondage. Txxx babes 3some 4some. Xhamster desi boobs. Pornhub virgin hardcore. Xhamster indian wife blowjob cute. Mylust amateur outdoor park sex. Mylust boobs girlfriend. Youporn german funny dutch.
All Models are over 18 y. X Hamster. All categories Indian videos. HD Videos videos. Reality videos. Daughter videos.