9个地方绵羊品种mtDNA D-loop高变区序列分析

对中国9个绵羊品种的103个个体mtDNA D-loop高变区(763 bp)进行了研究,结果表明:获得的序列长度范围为522～683 bp,可归为21种分子类型,各分子类型在绵羊品种间分布趋于一致,不存在特异性,而在品种内却存在异质性;绵羊mtDNA D-loop区序列长度变异主要是由于75 bp基元重复序列重复次数的不同(2、3或4个)和少数碱基的插入或缺失造成的;103个个体mtDNA D-loop区序列中A T碱基组成比例(64.7%)明显高于G C碱基组成比例(35.3%),说明了绵羊mtDNA D-loop区是A、T碱基富集区,且为高突变区,碱基突变类型包括转换、颠换、插入和缺失,且碱基转换频率远高于碱基颠换频率.

Sequence Analysis of mtDNA D-loop Higher-variable Region in Nine Sheep Breeds of China

103 blood samples of sheep individuals from nine sheep breeds of China were collected,and their higher-variable region sequence(763 bp) of mitochondrial DNA D-loop were studied.The results showed that the sequence length scope was 522 bp ~ 683 bp,and classified 21 kinds molecular types.Various molecular types tended to consistentiy in the sheep breeds tested,and there was no specific molecular types among sheep breeds,but had individual specificity within sheep breed.The length variation of mitochondrial DNA D-loop sequences of the sheep individuals tested derived from two sources: the different times of 75 bp tandem repeats motif(two,three and four times) and insertion or deletion of several nucleotide sites.A%+T%(64.7%)was higher than G%+ C%(35.3%),it explained that the sheep mitochondrial DNA D-loop region was concentration of nucleotide A and T,and genetic higher-variable region.The variation types of nucleotides sites included transition,transversion,insertion and deletion,and transition frequency was higher than that of transversion in the mitochondrial D-loop of Chinese sheep populations.