Gustafson N A, Gandolfi B, Lyons L A
Department of Veterinary Medicine & Surgery, College of Veterinary Medicine, University of Missouri - Columbia, Columbia, MO, 65211, USA.
Anim Genet. 2017 Feb;48(1):116-120. doi: 10.1111/age.12505. Epub 2016 Sep 27.
The Burmese is a breed of domestic cat that originated in Southeast Asia and was further developed in the United States. Variants in melanocortin 1 receptor (MC1R) causes common coat colour phenotypes in a variety of mammalian species but only limited colour variation in the domestic cat. Known as the extension (E) locus, melanocortin 1 receptor (MC1R) interacts with the agouti locus to produce the eumelanin and pheomelanin pigments. Recently, a novel reddish coloration, which is termed russet, was identified in the Burmese cat breed. Because this russet Burmese coloration changes with aging, MC1R was suggested as candidate gene. The similar colouration in specific lineages of Norwegian Forest cat known as amber (e) (c.250G>A; p.Asp84Asn) was excluded for this Burmese phenotype. The complete 954-bp coding region of MC1R was directly sequenced in russet Burmese and suspected carriers. A 3-bp deletion (c.439_441del) associated with the deletion of a phenyalanine (p.Phe146del) in the protein sequence was identified. All russet coloured cats were homozygous for the variant, and all obligate carriers were heterozygous, confirming that the deletion segregated concordantly with colouring in Burmese cats from the New Zealand foundation lineage. The variant was not identified in 442 cats from 26 different breeds and random-bred cats. Twenty-six Burmese from the USA did not have the variant. This MC1R variant defines a unique coloration and the second breed-specific MC1R variant in cats. The interactions of the two recessive feline MC1R alleles (E > e, e ) is unknown.
缅甸猫是一种家猫品种，起源于东南亚，并在美国得到进一步培育。黑皮质素1受体（MC1R）的变异在多种哺乳动物物种中导致常见的毛色表型，但在家猫中仅产生有限的毛色变异。黑皮质素1受体（MC1R）被称为延伸（E）位点，它与刺鼠信号蛋白位点相互作用，产生真黑素和褐黑素色素。最近，在缅甸猫品种中发现了一种新的微红毛色，称为赤褐色。由于这种赤褐色缅甸猫的毛色会随着年龄变化，MC1R被认为是候选基因。挪威森林猫特定谱系中被称为琥珀色（e）（c.250G>A；p.Asp84Asn）的类似毛色被排除在这种缅甸猫表型之外。对赤褐色缅甸猫和疑似携带者的MC1R完整954个碱基对的编码区进行了直接测序。鉴定出一个3个碱基对的缺失（c.439_441del），该缺失与蛋白质序列中一个苯丙氨酸的缺失（p.Phe146del）相关。所有赤褐色猫对该变异均为纯合子，所有必然携带者均为杂合子，这证实了该缺失与来自新西兰基础谱系的缅甸猫的毛色一致分离。在来自26个不同品种的442只猫和随机繁殖的猫中未发现该变异。来自美国的26只缅甸猫没有该变异。这种MC1R变异定义了一种独特的毛色，也是猫中第二个品种特异性的MC1R变异。两种隐性猫MC1R等位基因（E > e，e）之间的相互作用尚不清楚。
