半番鸭和北京鸭MC1R基因的克隆与序列分析

羽色是半番鸭一个重要的经济性状。黑素皮质素受体1 （melanocortin receptor 1，MC1R）基因是控制动物黑色素合成的重要基因。本研究根据鸡、鹌鹑、雪雁、孔雀等MC1R基因同源序列的保守区设计1对引物，以半番鸭、北京鸭总DNA 为模板，PCR扩增，克隆测序。结果，获得了2个长度为900bp 的基因片段, 并提交GenBank, 登录号分别为EU877265和EU877264。经比对，发现北京鸭与半番鸭核苷酸序列存在8个变异位点，其中位于184bp（T/A）、229bp（G/A）、364bp（A/G）、385bp（G/A）处的变异导致了氨基酸序列分别在第62位（C/S）、77位（E/K）、122位（T/A）和129位（V/I）发生突变。为进一步研究半番鸭羽色MC1R基因单核苷酸多态性（SNP）奠定了基础；通过BLAST进行相似性搜索，结果表明，鸭与黑雁MC1R基因的核苷酸序列同源性最高为98.4％，与其他家禽的同源性也保持在92.8％～98.2%之间。可见禽类的MC1R 基因编码区序列具有高度的保守性；系统进化分析表明,半番鸭、北京鸭与雪雁、黑雁、皇雁亲缘关系相近，从分子角度验证了它们在动物学分类上的地位。

Molecular Cloning and Sequence Analysis of MC1R Gene from Mule Duck and Anas Platyrhynchos

Plumage color is a important economy trait . Melanocortin 1-receptor(MC1 R)gene is a key gene in melanogenesis in mamma1.A pair of oligonucleotide primers were designed according to the conserved region of MC1R gene of gallus, coturnix japonica, anser caerulescens, and pavo cristatus. PCR amplifications , cloning and sequencing were performed on maxima DNA of mule duck and anas platyrhynchos. The results showed two fragments of 900bp were obtained , whose accession numbers were EU877265 and EU877264 in the GenBank, respectively. The 8 mutaions were found in the two fragments. The mutations in 184（T/A）,229（G/A）,364（A/G）and 385（G/A）led to the amino acid replacement at 62（C/S）,77（E/K）,122（T/A）and 129（V/I）, respectively. The results were the basic information to further study SNPs of MC1R gene associated with plumage color on mule duck. By using the program of Blast on GenBank, the results indicated that duck had homology with 98.4% homology with branta bernicla at nucleotide level of MC1R gene, and 92.8％～98.2% homology with other birds.The results demonstrated that MC1R gene of bird was relatively conserved. The results of phylogenetic analysis showed that consanguinity relations between mule duck, anas platyrhynchos and branta bernicla, anser caerulescens, anser canagica were close.The status of them were confirmed on zoologyl by means of molecular method.