应用微卫星标记对雌核发育银鲫的遗传多样性初探

Preliminary Investigation on Genetic Diversity of Gynogenetic Silver Crucian Carp (Carassius auratus gibelio Bloch) Detected by Microsatellite DNA

利用Crooijmansetal ( 1997)分离的包含CA重复单元的普通鲤鱼 (CyprinuscarpioL )的 8个微卫星DNA标记 ,对银鲫 (CarassiusauratusgibelioBloch)的 5个不同雌核发育系的 2 4尾个体进行PCR扩增。分析电泳结果发现 ,除MFW2 8未能在银鲫中稳定地扩增出相应的同源序列 ,其余的 7对引物扩增的重复性和稳定性都很好。随引物不同 ,各等位基因数为 1～ 14个 ,大小在 10 0～ 5 0 6bp。在MFW 1、MFW 4、MFW 19、MFW 2 0、MFW2 3和MFW2 4 6个微卫星的扩增图谱中 ,不同的雌核发育系扩增出各自独特的图谱。而同一系内的不同个体间具有高度的遗传同质性 ,但仍然在个别个体中检测到少量的多态片段。不同系间的扩增图谱呈现出高度的遗传异质性 ,共鉴定出 2 3个可以用于有效区分 5个不同雌核发育系的分子标记。这 5个微卫星标记反映了银鲫 5个雌核发育系间的相互亲缘关系。其中P和A系同属一个雌核发育系 ,F系起源于E系 ,A、D和E系可能分别独立地起源于不同的杂交事件。鉴定的微卫星分子标记为进行银鲫群体遗传学和进化遗传学研究 ,以及银鲫的分子标记育种和进行基因组作图提供了理想的工具。

individuals from five different gynogenetic strains of silver crucian carp ( Carassius auratus gibelio Bloch) were analyzed using 8 microsatellite markers of the poly (CA) type isolated from common carp ( Cyprinus carpio L ) by Crooijmans et al (1997).Electrophoretogram patterns showed that 7 pairs of microsatellite primers reproducibly produced the well identifiable and homologous DNA fragments except the primers of MFW28.The number of alleles per marker varied from 1 to 14,and the size of alleles ranged from 100 bp to 506 bp.Nearly identical banding patterns occurred among intra strain individuals,although subtle polymorphism was occasionally detected in the five strains.It was suggested that each strain might possess specific pattern owing to its gynogenesis.On other hand,the five strains differed from each other in electrophoretogram patterns.A total of 23 polymorphic fragments were scored from 5 pairs of primers after excluding bands that were monomorphic for the five strains.The electrophoretogram pattern clearly indicated their intra strain homogeneity,inter strain heterogeneity,and their phylogenetic relationships.Strain P is same to strain A,and strain F originates from strain E.Strains A,D and E may originate from different multiple events of hybridization respectively.The microsatellite markers produced by this study will be of benefit to further studies on the evolutionary genetics and provide useful tools for marker assisted selection breeding or genetic map.