›› 2019, Vol. 31 ›› Issue (8): 1257-1271.DOI: 10.3969/j.issn.1004-1524.2019.08.06

• Animal Science • Previous Articles     Next Articles

Genetic diversity analysis and RAPD identification of three successive generations of meio-gynogenetic population in Megalobrama amblycephala

TANG Shoujie1,2,3, BI Xiang4, ZHANG Feiming4, ZHANG Youliang4   

  1. 1. Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China;
    2. National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China;
    3. Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Ocean University, Shanghai 201306, China;
    4. Songjiang Aquatic Seed Breeding Farm, Shanghai 201616, China
  • Received:2019-01-31 Online:2019-08-25 Published:2019-08-30

Abstract: To assess the genetic diversity and genetic homozygosity of the three generations of meiotic gynogenetic populations of blunt snout bream (Megalobrama amblycephala), and to find a stable molecular genetic marker that distinguishes different breeding populations of M. amblycephala(Pujiang No.1 genetically selected strains F9, three consecutive generations of meiotic gynogenetic populations), genetic diversity and genetic structure of meiotic gynogenetic populations meio-G1 (the first generation), meio-G2 (the second generation), meio-G3 (the third generation) and the control group (Pujiang No.1 genetically selected strains F9) of M. amblycephala was analysed using thirty-nine RAPD markers in this study. Several stable RAPD markers for distinguishing different breeding populations were obtained. And the efficiency to pure gene for successive artificial meiotic gynogenesis in M.amblycephala was assessed. The results showed that: the number of loci detected in the control group, meio-G1, meio-G2 and meio-G3 were 213, 202, 200 and 190, respectively. The percentage of polymorphic loci detected in the control group, meio-G1, meio-G2 and meio-G3 were 36.15%, 35.64%, 27.00% and 26.84%, respectively. Shannon's information index estimated within the control group, meio-G1, meio-G2 and meio-G3 were 0.207 9, 0.185 7, 0.146 1 and 0.138 3, respectively. The genetic diversity of meio-G1, meio-G2 and meio-G3 were much lower than that in the control group.The genetic diversity of three consecutive generations of meiotic gynogenetic populations decreased with the increasing of gynogenetic generations. Genetic identity between individuals within each population ranged from 0.828 5 to 0.906 0. The genetic identity between individuals within populations of meio-G1, meio-G2 and meio-G3 were much higher than that in the control group. The genetic identity between individuals within three consecutive generations of meiotic gynogenetic populations increased with the increasing of gynogenetic generations. Genetic differentiation index (pairwise FST values) between four populations ranged from 0.269 2 to 0.419 5. And the probabilities of the permutation test of genetic differentiation between four populations ranged from 0.000 0 to 0.009 0, indicating extremely significant genetic differentiation between four populations. Five primers (S3, S40, S58, S71 and S75) were observed to produce specific bands for discriminating different populations. Of these primers, four primers (S3, S40, S58 and S75) could be used as molecular markers for distinguish between meio-G3 and the other three populations (F9, meio-G1 and meio-G2). Primer S3 has the highest reliability for population identification. Only one primer (S71) could be used as molecular markers for distinguish between meio-G2 and the other three populations (F9, meio-G1 and meio-G3).The results of this study indicated that the continuous generations of artificial meiosis gynogenesis had affected the breeding populations of M. amblycephala in the following two aspects: on one hand, the genetic diversity significantly reduced with the increasing of gynogenetic generations. On the other hand, the genetic purity increased significantly with the increasing of gynogenetic generations. Continuous multi-generation meiotic gynogenesis could significantly accelerate the homozygous rate of the gene, and the meio-G3 population was already a high-purity line with high genetic consistency.

Key words: Megalobrama amblycephala, gynogenesis, genetic diversity, RAPD marker

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