【作者】 伊新华；

【导师】 侯和胜；

【作者基本信息】 辽宁师范大学 ， 海洋生物学， 2010， 硕士

【摘要】 鼠尾藻是我国常见的暖温带海藻,具有较高的经济价值和营养价值。作为经济水产养殖动物的优质饵料,随着海参及鲍鱼养殖业的迅猛发展,其需求量也不断增加。目前鼠尾藻在我国尚未形成规模化养殖,仅靠年产量较低的自然繁殖和小规模的人工养殖,无法满足生产需要。尽管鼠尾藻养殖规模较小,但其养殖对野生鼠尾藻种菜的需求和依赖性较大,导致人们大量采集自然生长的鼠尾藻作为养殖种菜或直接作为海参等的养殖饵料,导致沿海地区的鼠尾藻种质资源遭到严重破坏。因此开展鼠尾藻的人工养殖种苗培育和优良品种开发的研究势在必行,同时其遗传多样性鉴定和种质资源保护也变得尤为重要。实验采用AFLP分子标记技术对大连5个野生鼠尾藻种群:庄河石城岛(SCD),瓦房店将军石(JJS),长海县大长山(DCS),旅顺董砣子(DTZ),旅顺盐场(YC)与山东蓬莱(PL) 1个种群共60个个体进行遗传多样性和亲缘关系分析。采用10对选择性扩增引物组合共扩增出条带530条,其中多态性带417条,多态性平均检出比例78.68%。AMOVA分析显示,在种群总的遗传变异中,大部分的遗传变异(76.58%)存在于种群内,少部分(23.42%)存在于种群之间。遗传分化系数Gst为0.2418,与Fst的值(0.2342)接近,表明鼠尾藻种群内部具有较高的遗传分化。UPGMA聚类分析可知,大连5个野生鼠尾藻种群与山东蓬莱鼠尾藻种群亲缘关系较远,明显聚为两支;大连种群中将军石和大长山两种群聚为一支,遗传相似系数为0.7698,再与董砣子种群聚类到一起;盐场种群单独聚为一支,与其它种群之间的遗传相似系数均在0.5830以下。分析结果表明,各鼠尾藻种群内部存在着较高的遗传多样性,而种群间的遗传多样性水平较低,其亲缘关系的远近不仅与地理隔离因素有关,局部高盐等外界环境胁迫也可能起到了一定的作用。本研究选用AFLP分子标记技术探讨了大连沿海5个野生种群和山东蓬莱1个野生种群鼠尾藻的遗传多样性,通过在分子水平上分析各野生种群内部和种群之间的遗传分化相关指数,计算各群体间的遗传距离及遗传相似性,生成聚类关系图谱,揭示了6个野生鼠尾藻种群的遗传多样性及其相互关系,这些遗传背景的初步揭示可以为野生鼠尾藻种质资源鉴定,人工育苗以及杂交育种技术中的亲本选择提供可靠的理论依据。更多还原

【Abstract】 Sargassum thunbergii is a common warm-temperate seaweed in China which has high economic and nutritional values. With the rapid development of sea cucumber aquaculture industry, the demand of S. thunbergii is also rising rapidly. But currently S. thunbergii culture have not formed large-scale farming, and the annual production was lower. Because S. thunbergii culture is quite dependent on the selection of seedling sources, and a large amounts of nature wild S. thunbergii was used as food of sea cucumber, S. thunbergii germplasm resources have been seriousely damaged. Therefore, the artificial cultivation of S. thunbergii is imperative, and its germplasm resources conservation and identification of genetic diversity have become particularly important.Amplified fragment length polymorphism (AFLP) was used to assess the genetic diversity of five wild populations of S. thunbergii in Dalian: SHICHENGDAO(SCD), JIANGJUNSHI(JJS), DACHANGSHAN(DCS), DONGTUOZI(DTZ), YANCHANG(YC) and a Shandong population: PENGLAI(PL). 530 loci were obtained using 10 combinations of selective primers. Of these loci, 417 were polymorphic, accounting for average 78.98% of the total. Analysis of molecular variance (AMOVA) revealed that a higher portion (76.58%) of variations was detected within populations, while a lower portion (23.42%) of variation was found among populations. The Gst value was 0.2418, which was consistent with Fst (0.2342), indicating strong genetic differentiation within populations. When integrated with the UPGMA dendrogram of the six populations, they can be clustered into two major groups. One was Shandong population, the other was Dalian populations; among Dalian populations, JJS and DCS were clustered into one group, reaching a coefficient of similarity 0.7698, but YC was lonely clustered into one group, whose coefficient of similarity was below 0.5830 comparing with the other five populations. The results showed that there was higher genetic diversity within the six populations, however it was lower among the populations; and that relationship of populations was decided not only on the geographical distance but also on the external environmental factors such as high salt and so on.Using AFLP molecular markers the study investigated the genetic diversity of S. thunbergii of five wild populations along the coast of Dalian and a wild population of Shandong Penglai. The analyzed index related to genetic differentiation within and between wild populations at the molecular lever, the genetic distance and genetic similarity between groups, UPGMA dendrogram, and the genetic diversity of the six wild populations of S. thunbergii. These will provide a strong theoretical basis and strong genetic background for development and cultivation of the germplasm resources.更多还原