ANALYSIS OF GENETIC HOMOZYGOSITY AND DIVERSITY OF TWO SUCCESSIVE GENERATION MEIO-GYNOGENETIC POPULATION IN PSEUDOSCIAENA CROCEA USING MICROSATELLITE MARKERS

Artificial induction of gynogenesis is one kind of chromosome manipulation with several applications,including rapid establishment of inbred lines or strains with high degree of homozygosity,sex-control,and accelerated elimination of recessive deleterious genes from aquaculture population.In our laboratory,meiotic gynogenetic populations meio-G1(the first generation) and meio-G2(the second generation) were successfully produced in large yellow croaker(Pseudosciaena crocea Richardson 1846).To assess the efficiency to pure gene for artificial meiotic gynogenesis in large yellow croaker,the homozygosity of the meio-gynogenetic populations for meio-G1 and meio-G2 was studied with microsatellite markers.The results showed that the average homozygosity among the fifteen analyzed loci were 0.661 and 0.803 in meio-G1 and meio-G2,respectively,which were much higher than that in the natural mating population(0.376 for the average homozygosity).The average similarity coefficient between individuals within meio-G1 and meio-G2 were 0.5903 and 0.8672,respectively,which were also higher than that in the natural mating population(0.4687 for the average similarity index between individuals).Value of diversity coefficient(Fst),genetic similarity and genetic distance showed significant genetic differentiation between the populations of meio-G2 and the natural mating population.Besides,seven out of analyzed loci(46.7%) were fixed in meio-G2,showing that the homozygosity of most genes can be accelerated by inducing meiotic gynogenesis in large yellow croaker.However,purity is hard to achieve in some loci for their telomerical location.For these loci,homozygosity can be gained by inducing mito-gynogenesis or control cross between individuals having same genotype.The information obtained in the study suggested that artificially induced meiotic gynogenesis is an efficient inbreeding method to pure the genome and increase the speed to establish pure-lines of large yellow croaker.The meio-gynogenetic populations cultivated in the study are useful for further selective breeding program.