作　　者： ; ; ; ; ;

机构地区： 华南农业大学动物科学学院

出　　处： 《中山大学学报（自然科学版）》 2012年第5期100-106,136,共8页

摘　　要： 研究了长江和珠江野生赤眼鳟Squaliobarbus curriculus共4个群体24个个体的线粒体控制区(D-loop)和细胞色素b(Cyt b)基因序列,通过PCR扩增与测序,分别获得了长度为598 bp和752 bp的D-loop和Cyt b基因片段。分析表明,D-loop序列共定义了18个单倍型,存在34个简约信息位点,67个多态性位点,发生转换40次,颠换15次,插入/缺失14次。A、T、C、G平均含量分别为33.7%、35.1%、17.5%、13.7%。Cyt b序列共定义了18个单倍型,存在68个简约信息位点,72个多态性位点,发生转换60次,颠换15次,无插入/缺失位点。A、T、C、G平均含量分别为29.3%、26.4%、29.8%、14.5%。Cyt b除简约信息位点百分比大于D-loop外,多态位点百分比和单突变位点百分比均小于D-loop,说明D-loop具有较快的进化速率。D-loop序列的单倍型多样性(H)、平均核苷酸差异数(K)、核苷酸多样性(π)分别0.963 8、16.543 5和0.028 4,Cyt b的H、K和π分别为0.971 0、31.855 1和0.042 6,显示赤眼鳟具有较高的遗传多样性水平,且遗传变异主要存在于群体间。分析群体间的遗传距离和FST值,D-loop和Cyt b都一致表明:长江和珠江水系间存在明显的遗传分化,系统树和分子变异等级分析(AMOVA)也支持这一观点。同一水系群体间的遗传差异较小,Cyt b则更小;不同水系群体间的遗传差异较大,Cyt b则更大。故,Cyt b呈现出"小则越小,大则越大"的态势。分析其原因,可能与D-loop和Cyt b进化速率密切相关。 Sequences of mitochondrial D-loop and Cyt b gene of 24 individuals of Squaliobarbus curriculus which were sampled from four populations in Yangtze River and Pearl River were determined.Using PCR amplification and sequencing,598bp of D-loop partial sequences and 752 bp of Cyt b partial sequences were obtained.In D-loop sequences,a total of 67 polymorphic sites defined 18 distinct haplotypes.And 34 parsim-info,40 transition,15 transversion and 14 insert/lacuna loci were found.The average content of A,T,C and G was 33.7%,35.1%,17.5% and 13.7%,respectively.In Cyt b sequences,72 polymorphic sites and 18 haplotypes were defined,and 68 parsim-info,60 transition,15 transversion and no insert/lacuna loci were found.The average content of A,T,C and G was 29.3%,26.4%,29.8% and 14.5%,respectively.The mean haplotype diversity（H）,the average number of nucleotide difference（K） and nucleotide diversity（π） for D-loop sequences were 0.9638,16.543 5 and 0.0284,respectively.Accordingly,the values for Cyt b were 0.971 0,31.855 1 and 0.042 6,respectively.The results suggested that both D-loop and Cyt b genes showed high genetic diversity in S.curriculus,among which the majority existed within populations.Based on population pairwise genetic distances and FST,there were obvious genetic differences between Yangtze River and Pearl River for S.curriculus.Molecular phylogenetic tree and analysis of molecular variance（AMOVA） also supported this result.The interpopulation genetic distances of Cyt b in the same water system were less than D-loop;while those in the different water system were more than D-loop.So for Cyt b,the more interpopulation genetic diversity was,the smaller genetic distances and FST were;the less interpopulation genetic diversity was,the larger genetic distances and FST were,which might be closely related to difference of evolutionary rate between D-loop and Cyt b gene.

关 键 词： 赤眼鳟 线粒体 遗传变异 对比分析

领　　域： [生物学] [生物学]