变态前牙鲆cDNA文库中I型微卫星的多态性分析

牙鲆（Paralichthys olivaceus）不仅是研究鱼类变态的模式生物，也是我国的重要水产养殖对象。从变态前牙鲆cDNA文库中的42个单一序列表达标签(ESTs)中筛选到46个微卫星分子标记，从中选择21个微卫星并在一个养殖牙鲆群体共30个样本中测试，结果表明其中有20个微卫星标记具有多态性，其等位基因数为2到6个，观察杂合度从0.06到1.00，期望杂合度从0.059 7到0.825 2变化不等，平均多态信息含量是0.457 5，可用于牙鲆连锁图的构建和分子标记辅助选育。其中，有3个微卫星位点的三核苷酸重复序列在基因编码区内，可能和基因功能有关。

Characterization of polymorphic type I microsatellite from cDNA library in premetamorphosing Paralichthys olivaceus

Oliver flounder, Paralichthys olivaceus, is not only a model animal for fish metamorphosis, but also an important cultured species in China. In this study, 42 unique expressed series tags (ESTs) containing 46 microsatellites were found from the cDNA library of premetamorphosing flounder. Twenty one microsatellite loci were tested in 30 individuals in the breeding population of P.olivaceus and 20 among them had polymorphism. The number of detected alleles varied from two to six, while the number of observed heterozygosity varied from 0.06 to 1.00, and the expected heterozygosity ranged from 0.059 7 to 0.825 2. The average of polymorphism information content (PIC) is 0.4575. The results indicate that these microsatellite loci will be useful for linkage map construction and marker assisted selection program of P.olivaceus. Three microsatellite loci with trinucleotide repeats buried in the coding region of genes were found to have polymorphism, which might be related to the gene function.