黄鳝野生群体和养殖群体遗传结构的RAPD分析

POPULATION GENETIC STRUCTURE OF RICE FIELD EEL (MONOPTERUS ALBUS) WITH RAPD MARKERS

采用RAPD标记技术对黄鳝野生群体和养殖群体遗传结构进行初步研究.用24个随机引物在野生群体和养殖群体中分别扩增出259和251条DNA片段,其中多态性片段数分别为116和92条,多态性片段的比例分别为44.79%和36.65%,平均杂合度分别为0.2155和0.1908,遗传相似率分别为0.9053和0.9583,群体间遗传相似率为0.8863.而Shannon遗传多样性指数表明,两群体中的遗传变异有81.51%来自群体内,只有18.49%来自群体间.野生群体的多态性位点比例和杂合度明显高于养殖群体,说明黄鳝野生种质资源状况较好,应加以合理保护.与野生群体相比,养殖群体的杂合度和遗传多样性有所下降,提示在黄鳝的人工繁殖过程中应引进标记辅助选择等技术手段.

The RAPD (random amplified polymorphic DNA) technique was applied to study the genetic structure of the wild population and raised population of Monopterus albus. Genomic DNA was extracted from 15 individuals of the wild and raised populations. Amplification with 24 random primers under predetermined optimal reaction conditions (samples were first heated at 94 ℃ for 4 min, and followed by 40 cycles of 1 min at 94 ℃, 1 min at 36 ℃, and 2 min at 72 ℃, then held at 72 ℃ for 10 min. after 40 cycles) generated 259 and 251 fragments of the wild and raised populations, respectively. The polymorphic fragments were 116 and 92, and the mean proportions of polymorphic amplified fragments of the wild and raised populations were 44.79% and 36.65%, respectively. The values of average heterozygosity for the two populations were 0.215 5 and 0.190 8, respectively. The genetic similarities for the populations were 0.905 3 and 0.958 3, respectively. The similarity between the populations was 0.886 3, and Shannon index of phenotypic diversity between the populations was 0.184 9. The higher value of the wild population indicated that the wild resource of M. albus was in good condition with higher genetic variability, and effective measures should be taken to maintain the good condition with higher genetic variability, and to keep the good status. The lower heterozygosity and genetic diversity in the raised population suggested that the approaches such as marker assisted selection should be introduced into eel breeding programs. Fig 1, Tab 3, Ref 24