七株眼虫基于微卫星DNA指纹图谱的区分和关系分析

研究了牛山湖小型鱼类的群落结构、种群密度和多样性．共捕获14种小型鱼类,以1龄鱼为主,其中红鳍原鲌、似鱎、麦穗鱼和鳑鲏是优势种群．小型鱼类的密度为5．9 ind／m2或14．0 g／m2．小型鱼类的群落多样性较低,以个体数为单位计算的Shannon-Wiener多样性指数为1．802,Simpson优势度指数为0．484, Pielou种类均匀度指数为0．503．水生植被是牛山湖小型鱼类群落分布的主要影响因子,水草生境中小型鱼类数量显著比无水草生境中多,水深和透明度对小型鱼类群落分布无显著性影响．通过合理调控湖泊鱼类群落结构和放养食鱼性鱼类来合理持续利用小型鱼类,有利于提高湖泊经济效益和生态效益．

Separation and relationships of seven Euglena strains based on microsatellite DNA finger-printing

The genetic relationships among Euglena strains remain poorly understood, despite a rich history of morphological examination and an extensive phylogenetic analysis of the ribosomal RNA genes. It is difficult to identify related species of the genus Euglena and to separate different strains of the same species because the morphological characters are variable and limited. We address this question using microsatellite DNA fingerprinting. Seven microsatellite loci were amplified from 7 Euglena strains. A total of 4-8 bands were successfully amplified for each of 6microsatellite primer pairs. Microsatellite DNA fingerprinting and similarity values ranging from 0.000 to 0.957 a-mong the seven strains were obtained, which were used to construct a similarity tree among them. According to the tree, at the linkage distance of 0.9346 seven strains were separated into three clusters: E. mutabilis, E. intermedia and E. gracilis consisting of Japanese and USA groups. Further, in the cluster E. gracilis, different genotypes were recognized for the strains from different geographical origins. The relationships among species and strains were analyzed preliminarily. We demonstrates that the seven strains of Euglena can be clearly separated by their microsatellite DNA fingerprinting patterns. The microsatellite DNA fingerprinting has a high resolution and is a new useful method to identify and separate similar species and intraspecific strains in free-living protozoa.