三疣梭子蟹Ⅰ型微卫星标记的发掘及多态性分析

Identification of type Ⅰ microsatellite markers and their polymorphism in Portunus trituberculatus

为发掘三疣梭子蟹Ⅰ型微卫星标记,实验运用生物信息学方法,从NCBI数据库已公开的13 985条三疣梭子蟹EST序列中搜索微卫星位点。结果显示,共搜索到287个微卫星位点,其中主要为二核苷酸重复序列(173个),占总数的60.3%;其次为三核苷酸重复序列(79个),占总数的27.5%;四、五、六核苷酸重复位点较少;在二核苷酸重复位点中,AC/GT重复位点最为丰富,占二核苷酸重复位点总数的53.8%,AG/CT重复次之,占二核苷酸重复位点总数的37.0%,AT和GC重复较少。挑选14个Ⅰ型微卫星标记在野生三疣梭子蟹群体中进行多态性检测,发现8个位点呈多态性,平均多态信息含量(PIC)和平均遗传杂合度(H)分别为0.57和0.63。其中6个多态性位点的PIC值大于0.5,呈现较高多态性特征。研究表明,基于三疣梭子蟹EST数据发掘Ⅰ型微卫星标记的方法切实可行。本研究发掘的Ⅰ型微卫星标记将为三疣梭子蟹遗传多样性评估、遗传连锁图谱构建和QTL分析提供有效的分子标记。

In the present study,typeⅠmicrosatellites of Portunus trituberculatus were screened from 13 985 ESTs in the NCBI database by bioinformatics approach.A total of 287 type Ⅰ microsatellites were identified,among which 173 were the type of dinucleotide repeat being the most abundant microsatellite and accounting for 60.3% of the identified microsatellite markers,and 79 were the type of trinucleotide accounting for 27.5%,while hexa-,penta-and tetra-nucleotide repeats were rare.Among the dinucleotide repeats,AC/GT was the most abundant type with percentage of 53.8%,followed by the AG/CT type with 37.0%,while AT and GC were rare.14 microsatellites were selected for polymorphism analyses,8 of them showed polymorphism in a wild population of P.trituberculatus.The mean PIC and heterozygosity values were 0.57 and 0.63,respectively.Among them,6 PIC of microsatellites greater than 0.5,showing high polymorphism.This study showed that the way of screening typeⅠmicrosatellite markers from EST data was feasible.These typeⅠmicrosatellites can be used for further study in genetic diversity,genetic mapping and quantitative trait loci（QTLs）identification in P.trituberculatus.