依据减数分裂特异基因判定三角褐指藻生殖方式的研究  

Study on the determination of Phaeodactylum tricornutumreproduction strategy with the presence of meiosis-specific genes

作　　者：郭栗[1] 杨官品[1] 

机构地区：[1]中国海洋大学海洋生命学院,山东青岛266003

出　　处：《中国海洋大学学报（自然科学版）》2013年第12期41-47,共7页Periodical of Ocean University of China

基　　金：国家科技支撑计划项目(2011BAD14B01);国家自然科学基金项目(31270408)资助

摘　　要：生殖方式既是重要的生物学特征,也关乎遗传改良策略的选择。在三角褐指藻(Phaeodactylun tricornutum)中,真核生物中广泛存在的有性生殖过程从未被观察到。除直接观察有性生殖过程和依据遗传后果判定,还可根据减数分裂特异基因存在与否判定是否存在有性生殖。在三角褐指藻基因组序列中搜索减数分裂特异基因,用ClustalX进行序列比,用Mrbaye3.2软件构建分子系统学树,进行分子系统学分析,发现三角褐指藻缺失7个减数分裂特异基因中的3个,分别是Hop1,Mnd1和Dmc1。不能观察到有性生殖时,绝大多数(或全部)减数分裂特异基因存在可佐证有性生殖存在,而这些基因缺失则意味着减数分裂丧失和专营无性生殖。因三角褐指藻缺失部分减数分裂特异基因,故推论其专营无性生殖。无性生殖可维持遗传稳定,研究结果有助于通过选择优良藻株培育三角褐指藻的优良品种。Reproductive strategy is an important biological characteristics of an organism, which also de termines the method of its genetic improvement. Direct description of sexual process and genetic conse quences of sexual reproduction may give eloquent proof of sexual reproductiom however sexual reproduc tion, a dominant reproductive mode among eukaryotes, has never been observed in Phaeodactylum tricor nutum. The presence of most or a whole set of meiosisspecific genes in a genome would suggest the main tenance of meiosis and implicitly sexual reproduction; while the absence of these genes would be consistent with the loss of meiosis and implicitly asexuality. In this study, the genome of P. tricornutum was searched for meiosisspecific genes. Molecular phylogenetic analyses of the genes found in P. tricornutum genome, which included multiple alignment with Clustal X and construction of phylogenetic trees with Mr baye3. 2, showed that P. tricornutum has lost 3 （Hop1, Mndl and Drncl） meiosisspecific genes. P. tri cornutum may maintain obligate asexual reproductiom it lost 3 of 7 meiosisspecific genes identified till present. Asexulity makes an organism stable genetically. Our findings will aid to breeding the elite clones of P. tricornuturn through selection.

关 键 词：三角褐指藻 减数分裂特异基因 有性生殖 无性生殖 克隆 

分 类 号：Q178.53[生物学—水生生物学]