【作者】 袁文华；

【导师】 刘楚吾；

【作者基本信息】 广东海洋大学 ， 海洋生物学， 2011， 硕士

【摘要】 多鳞鱚(Sillago sihama)俗称沙钻、船丁鱼,沿岸小型鱼类,分布于红海、印度洋、太平洋、我国沿海等,具有较高的经济价值。至今,多鳞鱚相关研究仅限于品种形态生物学,其遗传多样性的研究还未充分开展起来,尤其在多鳞鱚群体遗传变异方面还未有过分子水平的全面分析。多鳞鱚群体的遗传多样性是否已出现降低、群体结构是否已发生变化等情况尚不能确定。本文利用AFLP分子标记对海南(HaiNan,HN)、汕尾(ShanWei,SW)、湛江(ZhanJiang,ZJ)和阳江(YangJiang,YJ)的四个多鳞鱚(Sillago sihama)野生种群共120个个体进行了遗传多样性分析,计算了各群体间的遗传距离,构建了反映群体间关系的系统进化树。以期对四个地域的多鳞鱚野生种群的遗传多样性水平作出评估,为多鳞鱚的种质资源保护、优良品种的选育与遗传图谱的构建提供一定的理论基础。进而为人工繁育多鳞鱚提供合理的育苗和养殖策略,为多鳞鱚向养殖业发展提供基础性资料。主要研究结果如下:1.共采用14对引物对四个地域的多鳞鱚群体进行遗传多样性的AFLP分析,共得到扩增位点392个,其中多态位点333个,多态性比例达85.05%。在海南群体分析中,得到多态位点213个,多态性比例达54.21%;汕尾群体内,得到多态位点198个,多态性比例达50.51%;湛江群体内,得到多态位点175个,多态性比例达44.55%。阳江群体中,得到多态位点156个,多态性比例达39.88%。所用引物在各多鳞鱚群体中扩增得到的多态性比例适中,说明所选14对AFLP引物用于多鳞鱚遗传多样性的分析是可行的。2.对四种多鳞鱚 DNA扩增结果的聚类分析表明,湛江群体和阳江群体间的遗传距离最小,海南群体和阳江群体间最大。海南群体30个个体之间遗传距离的变异范围在0.1911-0.7087之间,平均遗传距离为0.2481;汕尾群体30个个体之间遗传距离的变异范围在0.0767-0.7010间,平均遗传距离为0.2367;湛江群体30个个体间遗传距离的变异范围在0.1071-0.6453间,平均遗传距离为0.2109;阳江群体30个个体之间遗传距离的变异范围在0.1877-0.6141间,平均遗传距离为0.1987。结果显示,海南群体个体间遗传距离最大,阳江群体个体间遗传距离最小,说明海南群体个体间的遗传变异程度最高,阳江群体个体间的遗传变异程度最低。3.在研究多鳞鱚群体总体的遗传分化时,所有群体120个个体总的遗传杂合度Ht为0.3107;群体内基因多样性Hs为0.1102;群体间基因多样性Dst为0.2005;群体间的遗传分化度Gst为0.6454。分子方差(AMVOA)分析显示变异78%来自群体间,22%来自群体内。Gst系数和分子方差分析均显示群体间的遗传分化较大。4.四个多鳞鱚群体的遗传相似度为0.5324-0.9472,平均为0.7006;香农指数Shannon(I)分布在0.1378-0.2191,平均为0.1748,遗传多样性处于中度偏低水平。UPGMA法构建的群体遗传关系聚类图显示海南群体和汕尾群体聚为单独的一支,湛江群体和阳江群体在各自的分支又分为两亚分支,其中海南和湛江群体的遗传距离最远,湛江和阳江群体遗传距离最近。更多还原

【Abstract】 Sillago sihama spreads widely in Red rea、Indian Ocean and Pacific Ocean ,also distributed in China coast , particular has a higher yield in western Guangdong. So far, researching works relevant with Sillago sihama were confined in the study of ecosystems. Researchs on genetic diversity of Sillago sihama has not been carried out fully. Especially , genetic variance was not analyzed by molecule markers. We needed to know whether genetic diversity was declined or not , so to find evidences for artificial breeding of Sillago sihama.The author studied the genetic diversity of 120 individuals in four Sillago sihama groups of HaiNan (HN)、ShanWei(SW)、ZhanJiang(ZJ)、YangJiang(YJ) , calculated the genetic distance among every group, established the phylogenetic tree among populations. These works will benefit the protesting of resources of Sillago sihama , also provide theory evidences for artificial breeding of Sillago sihama.The main results from AFLP fingerprinting and cluster analysis indicated:1. Adopting 14 primer pairs to analyse the genetic diversity of Sillago sihama , there are 392 amplified sites with 333 polymorphic sites, polymorphism proportion is 85.05%. In the analysis of HaiNan Sillago sihama group, We got 213 polymorphic sites, the polymorphism proportion is 54.21%; there are 198 polymorphic sites in ShanWei Sillago sihama group, the polymorphism proportion is 50.51%; 175 polymorphic sites in ZhanJiang Sillago sihama group, the polymorphism proportion is 44.55%; 156 polymorphic sites in YangJiang Sillago sihama group, the polymorphism proportion is 39.88%. The results show that the 14 pairs of primers fit to analysis the population resources of Sillago sihama by AFLP.2. For polygenetic relationship among Sillago sihama, genetic distances were calculated and used for constructing a dendragram by UPGMA clustering analysis. The results suggest that the relationship of ZhanJiang and YangJiang is more approximation, HaiNan and YangJiang is farthest. The similarity coefficient is between 0.1911 to 0.7087 in HaiNan and 0.0767 to 0.7010 in ShanWei , while the coefficience is between 0.1071 to 0.6453 in ZhanJiang and 0.1877 to 0.6141 in YangJiang. This means that the YangJiang has the most similarity meanwhile the HaiNan has the most abundance genetic diversity.3. Analyzing genetic variation among populations , We found that the genetic diversity among populations is 0.3107 , genetic diversity within populations is 0.1102 . This results show a great genetic differentiation among populations. While the genetic diversity indexs with populations is 0.6454 . AMVOA analysis indicated there are 78% genetic variation caused by different populations. Diversity indexs and AMVOA analysis all show genetic variation main caused by populations.4. Four sillago sihama populations genetic similarity distribute in 0.5324-0.9472, mean is 0.7006; Shannon index distribute in 0.1378-0.2191, mean is 0.1748. The results show that genetic diversity of sillago sihama is in a lower condition. Moreover, the clustering analysis in UM shows, that was 4 different geographic populations were divided into three groups, SW and HN populations clustered into one group,ZJ and YJ in one group; the farthest genetic distance is between HN and ZJ, the lest is between ZJ and YJ.更多还原