青石斑鱼微卫星标记的筛选及群体多态性分析

微卫星DNA,又称短串联重复序列(STR)或简单序列重复(SSR),是广泛存在于真核生物基因组中的简单重复DNA片段,一般每个重复单位仅1～6个碱基,重复数为10～20次,其中动物体中以双核苷酸(CA/GT)n最为常见。根据微卫星DNA核心序列两端的保守序列设计引物

Isolation and characterization of polymorphic microsatellite markers

Yellow grouper Epinephelus awoara is an economically important marine fish mainly distributed in northwest-Pacific,western central-Pacific and South China Sea,but the number of its population greatly decreased due to overfishing of grouper adults and juveniles,habitat damage and loss from bottom trawling, pollution,high demand for food and so on these years.E.awoara was listed in the 2005 IUCN Red List as a specie with DD(data deficient).Since molecular markers are very useful tools to estimate germplasm resources,variety identification,genetic diversity analysis and preparation of genetic linkage map,the microsatellites of E.awoara were isolated and thus its micosatellite markers and genetic diversity were analysed.Firstly a library of partial small size fractionated genomic DNA was constructed with the E. awoara from South China Sea.96 microsatellites in 28 recombinant positive clones were obtained through PCR screening the library with M13 universal primers and simple tandem repeats primer(CA)_(15).Among these microsatellites,there were 39 perfect ones(40.6%),30 imperfect ones(31.3%),7 compound perfect ones(7.3%)and 20 compound imperfect ones(20.8%).The results indicated that microsatellite sequences characterized by(CA/GT)n were abundant in genomic DNA of E.awoara.26 of 28 pairs of primers which were designed to analyze genomic DNA of E.awoara according to unique microsatellite flanking sequences with the software Primer 5.0 could be amplified expected bands,of which 13 microsatellite markers were assessed genetic diversity for 19 individuals.As a consequence,the data showed that the average observed heterozygosity(H_o),average expected heterozygosity(H_e),average polymorphism information content(PIC)and average Hardy-Weinberg departure value(D)of E.awoara were 0.598 2,0.508 0,0.472 2 and 0.150 3 respectively.The findings indicated that although the genetic diversity of E.awoara in South China Sea was rich,but it had been influenced by human behaviors to a certain extent.