【摘要】 目的探讨四川黑熊线粒体细胞色素C氧化酶亚基Ⅰ基因的特征。方法根据已经报道的细胞色素C氧化酶亚基Ⅰ(cytochromecoxidasesubunitⅠ,COXⅠ)基因设计引物、PCR扩增和直接测序,并用软件对四川黑熊及其他几个物种的COXⅠ基因序列及COXⅠ蛋白的氨基酸序列进行了分析。结果四川黑熊COXⅠ基因长1605bp,编码含514个氨基酸残基的前体蛋白。碱基的含量分别为A26.9%,C23.1%,G18.3%,T31.8%。起始密码子为“ATG”,终止密码子为“TAA”。蛋白质等电点为6.29,分子质量为57.2×103。以四川黑熊和已报道的其他6种动物的COXⅠ基因序列为数据构建的分子系统发育树表明在所比较的其他3种熊类中,四川黑熊和美洲黑熊的亲缘关系最近;在牛,狗和大鼠中,四川黑熊与狗的亲缘关系最近。结论四川黑熊COXⅠ基因的DNA序列和蛋白的氨基酸序列和其他动物的相应序列有很高相似性,表明COX基因在所比较的几个物种中具有高度保守性。更多还原

【Abstract】 Objective To explore the features of the cytochrome c oxidase subunit Ⅰ (COXⅠ) of Asian black bear Sichuan subspecies. Methods Primers were designed according published gene sequences of other bear species. A DNA sequence was amplified by PCR from the bear Sichuan subspecies’s hair-follicle tissue total DNA, then the PCR product was sequenced. The results were analyzed and a forecast analysis was carried on. Results The amplified COXⅠ gene of Sichuan black bear was 1 605 bp and contained a 1545-nucleotide open reading frame encoding 514 amino acid residues. The overall base composition of COXⅠ gene is 26.9 %, 23.1%, 18.3 %, and 31.8 % respectively to A, C, G, and T. The start codon of the COXⅠ is ATG, while the termination codon TAA. The protein’s pI is 6.29 and weight is 57.2×10 3 . The similarity analysis and phylogenetic tree analysis indicated that Sichuan black bear has closer relationship to American black bear, but not to brown bear and polar bear. Among dogs, caws and rats, it is closer to the former one. Conclusion There are high similarities in the DNA sequence, protein amino acid sequence of Asian black bear Sichuan subspecies with other bear species, indicating a high conservativity of COXⅠ in these involved species.更多还原