大菱鲆引进群体与国内累代繁养群体线粒体D-loop区部分序列的遗传多态性分析

采用PCR扩增和DNA测序技术，测定分析了引自冰岛和法国的大菱鲆两个引进群体以及1个国内累代繁养群体共60尾个体的mtDNAD-loop区部分序列的遗传多样性。结果表明，60尾个体中，扩增获得的mtDNAD-Loop区部分序列长度为739～759bp；共检测到46个变异位点，其中单一变异位点17个，简约信息位点29个；共检测出56个单倍型，各群体的单倍型多样度分别为冰岛1．000、法国0．950、累代繁养0．850。3个群体的核苷酸多态性分别为冰岛0．00797、法国0．01134和累代繁养0．00616。各群体间的遗传分化系数分别为冰岛＂US法国0．53441、冰岛＂OS累代繁养0．27723、法国VS累代繁养0．60725。虽然3个群体的遗传多样性都不高，但是各种群之间存在一定的遗传分化，可以分别作为单独的种群进行种质保存和利用，特别是法国种群与其他两个种群间的遗传距离更远，更具引种价值。

Genetic Diversity of partial mtDNA D-loop region among stocks of turbot Scophthalmus maximus recently introduced and long-farmed in China

The nucleotide diversity of mtDNA D-loop region in three turbot stocks in China,two recently introduced stocks originated from wild populations in Iceland（BP） and France （FP） ,and one long-farmed stock without definitive origin（JNP）,was analyzed. Twenty turbots were chosen in each stock and the partial sequences of mtDNA D-loop region were obtained by PCR amplifying and DNA sequencing. Among the 60 turbots analyzed, a range of sequence length of 739-759 bp of the partial mtDNA D-loop was determined, and a total of 46 polymor phic loci including 17 singleton polymorphic sites and 29 parsim-informative sites were detected. Fifty-six haplotypes were identified with the haplotypic diversity （H,） of 1. 000, 0. 950 and 0. 850 in BP,FP and JNP respectively. The nucleotide diversity of the three stocks was 0.007 97 （BP）, 0. 011 34（FP）, and 0. 006 6（JNP）. The fixation index of genetic distance between stocks of BP vs FP, BP vs JNP, and FP vs JNP was 0. 534 41, 0. 277 23 and 0. 607 25, respectively. There were certain genetic varieties among the three stocks, although the genetic diversity of these stocks was not high. Hence, these three stocks have the potential to be conserved and ex- plored individually. The FP is more valuable for the selective breeding than the other two stocks for its further segregation from the other populations estimated by the genetic distance.