大叶藻EST-SSR标记开发及其在大叶藻群体遗传多样性研究中的应用

EST-SSR marker development and its application in population genetic diversity analysis of Zostera marina

本研究从NCBI的EST数据库中下载大叶藻EST序列共计10 659条,从中得到SSR位点共65个,SSR发生频率为1.7%,平均分布距离为21.7kb。其中三核苷酸为优势重复类型,占49.2%,二核苷酸数量仅次于三核苷酸,占33.8%。基于65条含有SSR的EST序列,设计并合成了30对引物,其中26对引物的扩增产物单一,片段大小与预测的相近或较大。在由16个大叶藻个体组成的群体中,其中8对引物的扩增条带具有多态性。利用这8对引物对青岛汇泉湾大叶藻自然群体进行了遗传多样性分析,结果表明,8个SSR共检测出33个等位基因,平均每个SSR能检测出4.1个等位基因,多个遗传多样性参数表明,青岛汇泉湾大叶藻群体具有较高的遗传多样性(Ho=0.5382;He=0.577 6;I=0.560 7)。本研究开发的EST-SSR标记,可进一步丰富大叶藻SSR标记信息,为大叶藻分子生态和群体遗传研究提供更多的标记选择。

In this study, a total of 10 659 Zostera marina EST sequences were download- ed from NCBI database, from which 65 EST-SSR loci were searched with the frequency of 1.7% and the average distributing distance of 21.7 kb. Out of all the repetitive motifs, the tri- mer was dominant at a ratio of 49.2%, followed by the dimer at a ratio of 33.8%. Based on the searched 65 EST sequences, 30 pairs of primers were designed and synthesized, of which 26 pairs had amplification products with unambiguous bands at similar or larger size than expected.Using eight pairs of polymorphic primers in a population of 16 individuals, the genetic diversity of Z. marina population in Huiquan Bay, Qingdao was analyzed. A total of 33 alleles were ob- tained at an average of 4. 1 alleles per locus, and the genetic diversity of the investigated popula- tion was relatively high （Ho=0. 538 2; He=0. 577 6）. The EST-SSR markers developed in this study will provide data for molecular ecology and population genetics study of Z. marina.