Melanocortin 1 receptor variation in the domestic dog
Melanocortin 1 receptor variation in the domestic dog
复制标题
DOI：
10.1007/s003350010005
复制
发表时间：
2000-01-01
期刊：
影响因子：
2.5
通讯作者：
Barsh, GS
中科院分区：
文献类型：
--
作者：
Newton, JM;Wilkie, AL;Barsh, GS
黑皮质素1受体（Mc 1 r）由许多不同哺乳动物中的延伸基因座编码，其中功能丧失导致红色/黄色褐黑素的排他性产生，并且组成性激活突变导致黑色/棕色真黑素的排他性产生。在家犬中，具有野生型E等位基因的品种，例如，杜宾犬可以产生任何一种色素类型，而具有e等位基因的品种，例如，金毛寻回犬只产生黄色色素。然而，纽芬兰犬和类似品种的黑色被毛被认为是由一种不寻常的Aglr等位基因引起的，该等位基因编码Mc 1 r的生理配体。在这里，我们报告预测的狗Mc 1 r是317个残基的长度和96%相同的狐狸Mc 1 r。对杜宾犬、纽芬兰犬、黑色拉布拉多犬、黄色拉布拉多犬、平毛猎犬、爱尔兰塞特犬和金毛猎犬的比较发现了六种序列变异，其中两种，S90 G和R306 ter，分别与黑色/棕色煤和红色/黄色皮毛部分相关。R306 ter存在于黄色拉布拉多、金毛猎犬和爱尔兰塞特犬中;后两者具有相同的单倍型，但在R306 ter以外的三个位置与黄色拉布拉多不同。在一项针对194只狗和19个品种的更大调查中，除了红松狮犬之外，R306 ter和红/黄被毛完全一致。这些结果表明，e等位基因是由一个共同的Mc 1 r功能丧失突变，要么重新发生或受到基因转换在最近的进化史，并建议，等位基因和基因座的关系，狗毛色基因可能更类似于那些发现在其他哺乳动物比以前认为的。
The melanocortin 1 receptor(Mc1r) is encoded by the Extension locus in many different mammals, where a loss-of function causes exclusive production of red/yellow pheomelanin, and a constitutively activating mutation causes exclusive production of black/brown eumelanin. In the domestic dog, breeds with a wild-type E allele, e.g., the Doberman, can produce either pigment type, whereas breeds with the e allele, e.g., the Golden Retriever, produce exclusively yellow pigment. However, a black coat color in the Newfoundland and similar breeds is thought to be caused by an unusual allele of Agouti, which encodes the physiologic ligand for the Mc1r. Here we report that the predicted dog Mc1r is 317 residues in length and 96% identical to the fox Mc1r. Comparison of the Doberman, Newfoundland, Black Labrador, Yellow Labrador, Flat-coated Retriever, Irish Setter, and Golden Retriever revealed six sequence variants, of which two, S90G and R306ter, partially correlated with a black/brown coal and red/yellow coat, respectively. R306ter was found in the Yellow Labrador, Golden Retriever, and Irish Setter; the latter two had identical haplotypes but differed from the Yellow Labrador at three positions other than R306ter. In a larger survey of 194 dogs and 19 breeds, R306ter and a red/yellow coat were completely concordant except for the Red Chow. These results indicate that the e allele is caused by a common Mc1r loss-of-function mutation that either reoccurred or was subject to gene conversion during recent evolutionary history, and suggest that the allelic and locus relationships for dog coat color genes may be more analogous to those found in other mammals than previously thought.