【摘要】 采用聚合链式反应和直接测序方法测定石鸡和大石鸡线粒体DNA(m tDNA)控制区全序列,分析m tDNA 3个区的序列变异,比较两种石鸡的遗传变异。石鸡m tDNA控制区全序列长1 154 bp,大石鸡是1 157 bp。与大石鸡相比,石鸡m tDNA控制区在第187位,第1 060位和第1 110位缺失。两种石鸡之间,m tDNA控制区I区、II区和III区的序列变异率分别为5.70%,0.64%和3.22%,I区的变异速率最快。石鸡m tDNA控制区的碱基含量是:T32.13%,C27.17%,A26.43%和G14.23%,大石鸡的分别是T32.30%,C26.79%,A26.10%和G14.81%。t-检验分析显示,石鸡和大石鸡m tDNA控制区的4种碱基含量差异都极显著。两种石鸡间的遗传距离是0.038 4。根据分子钟计算,它们的分歧时间大约在190万年前。它们的物种形成主要受青藏高原的隆升和更新世第2次寒冷期的影响。更多还原

【Abstract】 Mitochondrial DNA control-region(mtDNA Dloop) can be divided into three domains,corresponding to the highly variable peripheral domains I and III and to the central conserved domain II of vertebrates.Polymerase chain reaction and direct sequencing methods were used to analyze the entire mtDNA D-loop in Chukar partridge(Alectoris chukar) and Przevalski partridge(A.magna).The aims are to infer sequence variation of the three domains of mtDNA D-loop gene and to compare the genetic variation between Chukar partridge and Przevalski partridge.D-loops were 1 154 nucleotides(nt) long in Chukar partridge,(1 157) nt in Przevalski partridge (nt187,1 060 and 1 110 were deleted in Chukar partridge).The sequence variation rates of domains I,II and III were separately 5.70%,0.64% and 3.22% between Chukar partridge and Przevalski partridge,which indicated the variation rates of domains I was the fastest.The nucleotide composition of Chukar partridge mtDNA D-loop was: 32.13% T,27.17% C,26.43% A,14.23% G,and 32.30% T、26.79% C、26.10% A,14.81% G of Przevalski partridge.There were very significant differences in the contents of the four nucleotides between Chukar partridge and Przevalski partridge.Genetic distance was 0.038 4 between the two partridges.The calibrated rates of molecular evolution suggested that they speciated about 1.90 million years ago,affected by the uplift of Qinghai-Tibet Plateau and the Pleistocene second frigid stage.更多还原