| In this paper, the conditions of induction of meiotic gynogenetic diploid in large yellow croaker (Pseudosciaena crocea) were optimized and the development of genogenetic hapoid and diploid embryos was observed. The gene homozygosity and inbreeding coefficient of 1st and 2nd generations of meiotic gynogens (meio-G1 and meio-G2) were evaluated by using microsatellite markers. The recombination rates between 22 microsatellite markers and the centromere was analyzed in the induced meio-gynogenetic families. The main results were shown as follows:1. The conditions of induction of meiotic gynogenetic diploid in large yellow croaker, including UV radiation dosage for genetically inactivation of sperms, the starting time and duration of cold shock treatment for chrosome set duplication were optimized. Hertwig effects were observed in the survival rate of gastrula embryos and hatchability when eggs fertilized with UV irradiated semen. It was suggested that the appropriate dosage of UV to genetically inactivate sperm of large yellow croaker was 253800μw.cm-2 to 406080μw.cm-2. An orthogonal experiment in three factors and three levels was designed to investigate the effects of irradiation dose, the starting time of cold shock and the duration of cold shock on induced gynogenetic diploid in large yellow croaker. The results showed the hatching rate of genogenetic diploid with highest of 20% when the egg inseminated with semen irradiated with UV for 355320μw .cm-2, and cold shocked for 10 min started at 3 min post insemination.2. The variation of heterozygosity (H) and inbreeding effects in meio-G1 and meio-G2 were analyzed by using micromsatellites. Six micromsatellite loci were investigated in common cultured stock (C), meio-G1 and meio-G2. A total of 21 different alleles were found in all the 6 loci in the present study. Among the 3 population, the number of alleles were ranged from C (21) > meio-G1 (20) > meio-G2 (13). The average observed heterozygosity (Ho) of the meio-G1 and meio-G2 populations were 0.195 and 0.031, respectively, significantly less than that in C (0.494), and the Ho of meio-G2 was decreased 84.1% comparing to meio-G1. The observed inbreeding coefficient of the meio-G1 and meio-G2 population reached 0.605 and 0.937, respectively. This results suggest that gynogenesis is an effective method to pure the genome and useful for quickly establishing pure-lines in aquaculture.3. Twenty-two microsatellite (MS) loci which were demonstrated heterozygous in the female parents were used to evaluate the inheritance in two meio-G1 families and their control families of normal diploid. Four of the 22 microsatellite loci were deviated significantly from Mendelian expectations, and the other 18 loci were observed followed the Mendelian's segregation. The recombination rates (y) were ranged from 0 to 1.0 with an average y value of 0.586 in the 18 loci, corresponding to a fixation index of 0.414, which showed 1.67 times comparing to full-sib inbreeding. The map distances between MS loci and centromere from 0 to 50cM under the assumption of complete interference for these 18 loci. Among which, 10 loci showed high M-C recombination with frequency more than 0.667. The results indicated that high recombination existed in the meio- G1.
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