Genetics of Sex-linked yellow in the Syrian hamster.
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 Cys115Tyr 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.
Alizadeh
Azita
A
Department of Genetics, Stanford University, Stanford, CA 94305, USA.
Hong
Lewis Z
LZ
Kaelin
Christopher B
CB
Raudsepp
Terje
T
Manuel
Hermogenes
H
Barsh
Gregory S
GS
D054366:Agouti Signaling Protein / Q000235:genetics; D000818:Animals; D006224:Cricetinae; D004843:Epistasis, Genetic / Q000502:physiology; D005260:Female; D008040:Genetic Linkage; D014644:Genetic Variation; D005828:Genetics, Population; D006200:Hair Color / Q000235:genetics*; D008297:Male; D008647:Mesocricetus / Q000235:genetics* / Q000502:physiology; D008954:Models, Biological; D010375:Pedigree; D010641:Phenotype; D044102:Receptor, Melanocortin, Type 1 / Q000235:genetics; D014960:X Chromosome / Q000235:genetics*
D054366:Agouti Signaling Protein; D044102:Receptor, Melanocortin, Type 1; C515183:a protein, mouse