微卫星分子标记辅助镜鲤家系构建

Families construction assisted by microsatellite markers in mirror carp Cyprinus carpio L.

用微卫星标记辅助进行镜鲤(Cyprinus carpio L.)家系的建立及选育,通过对亲本遗传结构及遗传差异的分析,预测产生优良家系的最佳配组。用28个微卫星分子标记评估松浦镜鲤亲本群体的遗传潜力,结果显示,群体的多态信息含量(PIC)达到0.5627,处于高度的遗传多样性水平,具备进一步繁育筛选优良群体的潜质。用x2检验和遗传偏离指数(d)估计Hardy-Weinberg平衡,结果表明群体处于平衡状态,但在16个位点表现出杂合子缺失,这可能跟长期的人工选择有关。依据个体间的遗传距离,连续2年共建立1对1亲本的繁育家系70个,用网箱分别养殖,2月龄家系体长均值为7.24～10.60cm,体质量均值为14.02～40.63g,方差分析显示家系间体长、体质量差异均极显著;对其中4个家系1龄鱼种生长情况及遗传结构分析也表明家系间的遗传分化较大,近交系数(Fst)达到0.1537,家系的多态信息含量在0.3056～0.4077之间,保持中度多态水平。由子代家系的生长和遗传结构两方面的实验结果证实了微卫星在辅助家系建立尤其是亲本选配方面具有较好的预测性,所获得的家系差异较大,具备进一步选育优良家系的潜力,从而证实了用此方法对现有镜鲤种质进行遗传改良是可行的。

Superior family can be established and selected from optimum breeding pairs by means of microsatellite markers to analyze genetic structure of reproductive population. In this study, twenty-eight markers were used to evaluate the genetic potential of reproductive population including 131 samples （76 females and 55 males） of mirror carp （Cyprinus carpio L.）. Totally 146 alleles were detected ranging from 108 bp to 400 bp. Several genetic parameters were used to evaluate the parental population. The average number of alleles was 5.214 3 and the effective alleles mean was 3.058 5. The value of mean observed heterozygosity was 0.572 2 and the value of mean expected heterozygosity was 0.597 2. The mean value of polymorphic information content was 0.562 7, which indicates that the genetic variability was relatively high and selection of excellent population is possible. The population accorded with Hardy-Weinberg equilibrium checking by x2 test and genetic departure index, but heterozygote deficit of sixteen loci occurred such as HLJ049, HLJ057 and HLJ343 after a long time＇ s artificial selection. A total of seventy families were established based on genetic distance of breeding pairs after two consecutive years. The offspring of each family were cultured separately in net-cage. The body length of the two months old family ranged from 7.24 cm to10.60 cm and body weight were from 14.02 g to 40.63 g. The differences of body length and body weight were significant among families. The later study results of growth and genetic structure to the four families of one year old from 2006 indicated that there were significant genetic differentiation and the Fs, value was 0.153 7. The PIC ranged from 0.305 6 to 0.407 7, which revealed that the four families were detected in medium diversity. These results demonstrated that microsatellite could be used for assisting families selection due to its capacity to predict growth superiority of offsprings. It was feasible to use this method for genetic improvement of the mirror carp. [Journal of Fishery Sciences of China, 2008,15 （6） ： 893-901 Key words：