TYRP1 and MC1R genotypes and their effects on coat color in dogs.
We used PCR amplification of cDNA prepared from skin biopsies to determine the nearly full-length, protein-coding sequence of dog TYRP1, and to define sequence variants potentially responsible for the B locus. One common variant contained a premature stop codon in exon 5 (Q331ter), and the other deleted a proline residue in exon 5 (345delP). A third variant in exon 2 (S41C) occurred less frequently. We genotyped 43 brown (including brown and white) and 34 black (including tricolor, black-and-tan, and black and white) dogs. All 43 of the brown group carried two or more of these sequence variants likely to interfere with TYRP1 function, whereas 0 of 34 in the black group carried two or more of these variants (10 carried one variant). We also genotyped 13 black-nosed and 10 brown-nosed dogs whose coat color was described as red, yellow, gold, apricot, or orange (including various degrees of white). All these dogs were homozygous for a R306X MC1R variant shown to be associated with these coat color phenotypes. The black or brown nose correlated perfectly with the absence or presence of the same three TYRP1 variants described above. TYRP1 was linkage mapped to dog chromosome 11, with a SNP in exon 7.
Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5A8. schmutz@sask.usask.ca
Sheila M
SM
Schmutz
Tom G
TG
Berryere
Angela D
AD
Goldfinch
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D004285:Dogs / Q000145:classification / Q000235:genetics*; D005787:Gene Frequency; D005838:Genotype; D006200:Hair Color / Q000235:genetics*; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D009297:Nasal Mucosa / Q000378:metabolism; D009666:Nose / Q000033:anatomy & histology; D010088:Oxidoreductases; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D018043:Receptors, Corticotropin / Q000737:chemistry / Q000235:genetics*; D044101:Receptors, Melanocortin; D017386:Sequence Homology, Amino Acid
D008562:Membrane Glycoproteins; D018043:Receptors, Corticotropin; D044101:Receptors, Melanocortin; D010088:Oxidoreductases; C489799:TYRP1 protein, human