缢蛏(Sinonovacula constricta)EST-SSR 分布特征及引物开发利用

采用CAP3软件对NCBI上的5296条缢蛏ESTs序列进行了微卫星特征分析。结果表明,经拼接、去冗得到非冗余EST序列3453条,含SSR位点的EST序列267条,共307个SSR位点,检出率为8.89%,平均每6.83kb出现1个SSR位点。设计了40对EST-SSR引物并进行PCR扩增,29对引物能扩增出理想的PCR产物,其中多态性引物14对。利用14对多态性引物分析了乐清湾缢蛏遗传多样性,共检测到等位基因数(Na)61个,每个位点的等位基因数为2—12个。二核苷酸、三核苷酸和四核苷酸重复是最主要的重复类型,分别占15.96%、37.13%和35.50%。乐清湾缢蛏群体观测杂合度(Ho)、期望杂合度(He)和多态信息含量(PIC)分别为0.569、0.490和0.449,表明乐清湾缢蛏遗传多样性较丰富。

CHARACTERIZATION, DEVELOPMENT AND UTILIZATION OF EST-DERIVED MICROSATELLITES IN SINONOVACULA CONSTRICTA

A set of 5296 expressed sequence tags (ESTs) of Sinonovacula constricta from NCBI were screened using CAP3.0 software. After assembly, a total of 3453 non-redundant EST sequences were mined and yielded 267 non-redundant sequences which contained 307 putative SSRs accounted for 8.89% of the total number of EST sequences. This is equivalent to one EST-SSR per 6.83kb of sequence. Di-, Tri- and Tetranucleotide repeats EST-SSRs were dominant, counting for 15.96%, 37.13% and 35.50% respectively. Forty primers were designed for partial EST-SSRs and used for PCR amplification with 29 primer pairs showing amplifications while 14 were polymorphic. These were used to conduct SSR analyses of genetic variations of the 40 individual samples of S. constricta collected in Yueqing Bay. A total of 61 alleles were detected, with the number of alleles ranging from 2 to 12. The observed heterozygosity (H_o), expected heterozygosity (H_e) and polymorphism information content (PIC) were 0.569, 0.490 and 0.449, respectively. All of these parameters indicate that the S. constricta of Yueqing Bay rich genetic variation.