中文摘要：

为了评价E（extension）座位对牛毛色性状的影响,采用DNA序列分析和PCR-RFLP技术对云南地区4个黄牛群体（3个本地群体和1个引进品种）的黑素皮质素受体1（MC1R）基因的编码区进行了基因特征分析和群体变异检测。结果,在文山黄牛、昭通黄牛和短角牛中发现E＋和e2种等位基因,检测到E＋/E＋、E＋/e和e/e3种基因型。在文山黄牛中E＋和e等位基因的频率分别为0.54和0.46,在昭通黄牛中分别为0.70和0.30;而在迪庆黄牛中共检测到E＋、ED和e3种等位基因,它们的频率分别为0.76、0.14和0.10,该群体存在E＋/E＋、ED/ED、E＋/ED、E＋/e和ED/e5种基因型,未发现e/e型个体。与所研究个体的毛色性状相联系,发现E座位对牛的毛色有重要影响,E＋和ED等位基因与黑色表型有关,而e等位基因与红色表型有关,但黄色、棕色和红色表型还与其它座位基因相关联。

英文摘要：

In order to evaluate the influence of the extension （E） locus on the color of cattle′s coat, the genetic characteristic and variations of the encoding region for melanocortin-1 receptor （MC1R） gene in four cattle populations sampled in Yunnan Province, including three indigenous populations and an imported breed, were assayed and analyzed by using DNA sequencing and PCR-RFLP techniques. The alleles E＋, e and genotypes E＋/E＋, E＋/e, e/e were identified in Wenshan Yellow cattle, Zhaotong Yellow cattle and Shorthorn cattle. The frequencies of E＋ and e alleles were 0.54 and 0.46 in Wenshan Yellow cattle, 0.70 and 0.30 in Zhaotong Yellow cattle. The alleles E＋, ED and e were identified in Diqing Yellow cattle with the frequencies of 0.76, 0.14 and 0.10, respectively. The genotypes E＋/E＋,ED/ED, E＋/ED, E＋/e and ED/e were identified in Diqing Yellow cattle, with the only exception of e/e. In contact with the coat color of the selected samples, it was found that E locus had an important influence on determinating the color of the cattle′s coat. E＋ and ED alleles were associated with black coat, and e allele was connected to red coat. Whereas yellow, brown and red fur were also influenced by other loci.