文蛤微卫星DNA的筛选及其特性分析

采用磁珠富集分离法从文蛤(Meretrix meretrix)的基因组中筛选得到49条微卫星DNA序列,其中两碱基重复有3种类型36个序列,四碱基重复有14种类型26个序列.重复次数在5～30之间的序列占75.6%,30次以上重复的序列占24.4%,最高重复次数为100.根据重复单元的排列特点,完美型、非完美型及混合型序列所占比例分别为61.2%、14.5%和24.5%.本研究中构建的文蛤微卫星文库将在文蛤种质资源评价及分子遗传学研究中发挥作用.

Microsatellite Enrichment by Magnetic Beads in Meretrix meretrix and Characteristic Analysis

The asiatic hard clam Meretrix meretrix is of great commercial value for the marine cultivation industry in China.To assist genetic studies in this species,we have reported the isolation and characteristic of microsatellite DNA in Mmeretrix.Two 5' biotinylated probe(CA)_(15) and(GA)_(15) were used to hybridized,and hybridized fragments were captured by streptavidin-coated magnetic beads.The positive clones containing microsatellite sequences were screened by the PCR technique,and 49 clones were found contained microsatellite repeat sequences with more than 5 repetitions.The microsatellite sequences could be categorized structurally as follows,perfect(61.2%),imperfect(14.5%) and compound(24.5%).Besides the motif of CA and GA contained in the oligoprobe,we also found a lot of four nuclotide repeats.Among the microsatellite repeats,relatively short arrays(5～30 repeats)were most abundant(75.6%),and the largest array contained 100 repeats.The(CA)n and(GA)n enriched library created in this study would be useful resource for developing additional anonymous microsatellite markers of Meretrix meretrix in the future.