雌核发育草鱼的遗传结构分析和微卫星鉴别方法的建立

采用微卫星标记检测草鱼群体的遗传多样性,并根据纯合度的变化建立了雌核发育草鱼的鉴别技术。结果显示,8个位点共扩增出33个等位基因;在普通草鱼中,平均纯合度和PIC分别为0.203 1和0.552 8;在雌核发育群体中,则为0.716 1和0.357 2;2个群体间遗传相似度为0.873 3。其中,5个位点在雌核发育草鱼中纯合度明显提高,雌核发育草鱼在这5个位点的扩增总条带数为5~7个,普通草鱼则为8~10个,由此可100%区分2个草鱼群体。通过概率计算,理论鉴别概率达到99.92%。研究表明,雌核发育技术对草鱼的群体遗传结构改变较大,是快速建立纯系、固定优良性状的有效手段;根据群体遗传纯合度的改变、扩增条带数目差异,应用多态性微卫星分子标记可以简单、有效地区分雌核发育群体(或与之相似的高度近交群体)与普通群体。

Genetic structure analyses and microsatellite identification of gynogenetic grass carp(Ctenopharyngodon idella)

It is difficult to distinguish the gynogenetic fish from common one by morphology and physiology of grass carp(Ctenopharyngodon idella).To establish a molecular method of distinguishing the two groups,an artificially induced gynogenetic grass carp group was produced by activating grass carp eggs by the ultraviolet light(UV)irradiated common carp(Cyprinus carpio)sperm and subsequently blocking the release of the second polar body(PB2).Eight microsallite markers were detected,among which five markers were selected to establish a microsatellite identification method.33 alleles were amplified on 8 loci.The average value of observed homozygosity and polymorphism information content(PIC)were 0.203 1 and 0.552 8 in the common group,and those were 0.716 1 and 0.357 2 in the gynogenetic group,respectively.The genetic similarity between the two groups was 0.873 3.And then five microsatellite markers were used for genetic identification of gynogenetic grass carp.The total numbers of alleles at these five loci were between 5 and 7 for 48 gynogenetic grass carp,while those were between 8 and 10 for 48 common grass carp.So we can completely distinguish the two groups of grass carp according to the number of alleles amplified at the five loci.The probability of identification of the gynogenetic grass carp reached 99.92%,premised on the theory of probability calculation.In conclusion,the genetic homozygosity in the gynogenetic group was much higher than that in the common group,and therefore the gynogenesis technique was an effective method to quickly establish pure line and fix merits.Using polymorphic microsatellite markers can distinguish gynogenetic group(or highly inbred population)from common group according to the variation of genetic homozygosity.