摘要:
通过对大黄鱼(Pseudosciaena crocea)异质雌核发育一代群体(meio-G1)与二代群体(meio-G2)微卫星位点的纯合度进行分析,研究异质雌核发育对大黄鱼基因纯化的效率。结果显示:meio-G1和meio-G215个微卫星座位的平均纯合度分别为0.661和0.803,纯合位点比例最高个体分别为0.867(13/15)和0.933(14/15),两个群体内个体间的平均相似系数分别为0.5903和0.8672,最高分别达0.9286和1.0(遗传距离为0.0741和0),远高于两性交配繁殖群体(平均纯合度0.376,平均相似系数0.4687,个体间最小遗传距离0.2288);其中meio-G2群体有7个位点(46.7%)已经完全纯合固定,并与普通养殖群体产生较明显的遗传分化;表明人工诱导异质雌核发育可大大加速大黄鱼大多数基因位点的纯合,是快速建立高纯品系的有效手段。但不同位点的纯合度差异很大,部分位点在异质雌核发育后代中迅速纯合,在meio-G1中就达到很高的纯合度,而有些位点则在meio-G1和meio-G2中仍保持很高的杂合度;meio-G1和meio-G2群体中不同个体纯合位点比例差异也很大。研究培育的雌核发育群体为大黄鱼进一步选育提供了良好的遗传材料。
关键词:
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大黄鱼
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微卫星
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雌核发育
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纯合度
Abstract:
Artificial induction of gynogenesis is one kind of chromosome manipulation with several applications,including rapid establishment of inbred lines or strains with high degree of homozygosity,sex-control,and accelerated elimination of recessive deleterious genes from aquaculture population.In our laboratory,meiotic gynogenetic populations meio-G1(the first generation) and meio-G2(the second generation) were successfully produced in large yellow croaker(Pseudosciaena crocea Richardson 1846).To assess the efficiency to pure gene for artificial meiotic gynogenesis in large yellow croaker,the homozygosity of the meio-gynogenetic populations for meio-G1 and meio-G2 was studied with microsatellite markers.The results showed that the average homozygosity among the fifteen analyzed loci were 0.661 and 0.803 in meio-G1 and meio-G2,respectively,which were much higher than that in the natural mating population(0.376 for the average homozygosity).The average similarity coefficient between individuals within meio-G1 and meio-G2 were 0.5903 and 0.8672,respectively,which were also higher than that in the natural mating population(0.4687 for the average similarity index between individuals).Value of diversity coefficient(Fst),genetic similarity and genetic distance showed significant genetic differentiation between the populations of meio-G2 and the natural mating population.Besides,seven out of analyzed loci(46.7%) were fixed in meio-G2,showing that the homozygosity of most genes can be accelerated by inducing meiotic gynogenesis in large yellow croaker.However,purity is hard to achieve in some loci for their telomerical location.For these loci,homozygosity can be gained by inducing mito-gynogenesis or control cross between individuals having same genotype.The information obtained in the study suggested that artificially induced meiotic gynogenesis is an efficient inbreeding method to pure the genome and increase the speed to establish pure-lines of large yellow croaker.The meio-gynogenetic populations cultivated in the study are useful for further selective breeding program.
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