中华鳖太湖养殖种群和日本引进种群线粒体DNACytb基因片段序列分析及分子进化初探

PRELIMINARY STUDY ON MITOCHONDRIAL CYTOCHROME b DNA SEQUENCES AND PHYLOGENY OF PELODISCUS SINENSIS FROM TAIHU CULTURED POPULATION AND JAPAN-INTRODUCED POPULATION

对中华鳖太湖养殖种群和日本引进种群共38个个体的线粒体DNA细胞色素b基因中间部分序列进行测定,比较其同源性,计算碱基组成,并用乌龟为外群构建不同单倍型的UPGMA和NJ分子系统树。在获得的408bp的序列中,A+T约占58·8%,其中15个核苷酸位点存在变异(约占3·7%)。两种群共有6种单倍型(haplotype),其中太湖养殖种群有4种单倍型,日本引进种群有2种单倍型。由系统树显示,中华鳖太湖种群的4种单倍型聚合成一大支,日本引进种群的2种单倍型以很高的置信度(99%)聚成一支。两种群序列上的差异,可以成为种群鉴别的分子标记。

The mtDNA Cyt b fragments （408bp） in 38 individuals of Pelodiscus sinensis from Taihucultured population and Japan-introduced population were sequenced. The sequences were compared between the two populations. The base compositions were calculated, and the molecular phyiogenetic trees also were constructed by UPGMA and NJ methods using Chinemys reevesii as outgroup. In the sequences, the average of A＋ T （%） was about 58.8% and 15 nucleotied sites （about 3.7%） were found to be polymorphic. There were altogether 6 hapiotypes between both populations. Of which 4 were to occur m the population from Taihu and 2 to occur in Japanese population assembled. The UPGMA trees and NJ trees indicated that all the hapiotypes of Taihu＇s population assebled a big branch, while all the hapiotypes of Japanese population assembled one branch with high confidence level （99%）. Therefore, the sequence variation between the two populations may be used as molecular marker for distinguishing the different populations.