Research
| Title： | Two generations of meiotic gynogenesis significantly elevate homogeneity and confirm genetic mode of sex determination in bighead carp (Hypophthalmichthys nobilis) |
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| First author： | Pang, Meixia; Yu, Xiaomu; Zhou, Ying; Wang, Zhongwei; Chen, Geng; Luo, Weiwei; Feng, Xiu; Wang, Xinhua; Liu, Haiyang; Fu, Beide; Tong, Jingou |
| Journal： | AQUACULTURE |
| Years： | 2022 |
| DOI： | 10.1016/j.aquaculture.2021.737461 |
| Abstract： | Gynogenesis is an effective technique for establishing pure line and validating possible chromosomal mode of sex determination in fish. As one of the major aquaculture fish historically cultured in China, bighead carp (Hypo-phthalmichthys nobilis) is famous for its market value of the head, but slow in its genetic improvement due to a long period of sexual maturation. In this study, females of bighead carp (F0 dams) with fast growth and bigger head were chose to induce first and second generation of meiotic gynogenesis (GF1 and GF2 for short) by using UV-irradiated heterologous sperm of common carp (Cyprinus carpio). On average, diploid gynogens were obtained by cold shock with a survival rate of 7.36% for GF1 and 6.24% for GF2, respectively. Results of morphology comparison and parentage assignment showed that all survival gynogens were genetically derived from the dams. Compared with their F0 parents, heterozygosities of GF1 and GF2 gynogens decreased by 42% and 60% when analyzed using 50 SSRs, and by 35% and 53% when using 1505 SNP markers, respectively. Sexing of the GF1 and GF2 gynogens showed all-female genotypes and phenotypes when examined by male-specific DNA markers, histology section and morphology of gonads. Overall, large number of meiotic gynogens have been successfully induced in two consecutive generations, providing valuable resources for fast domestication and genetic improvement in bighead carp. Our evidence of sex ratios in both GF1 and GF2 gynogens also strongly supports a proposed chromosomal mechanism of sex determination (XX/XY) for this large-size cyprinid fish. |
