In this study reproduction by meiotic gynogenetic diploids and mitotic gynogenetic doubled haploids were carried out in Japanese flounder,Paralichthys olivaceus, by the same fertilized eggs from one female.The process of meiotic diploids and mitotic diploids produced involves two steps.First,the DNA of the sperm is fragmented by UV irradiation.Next,the meiotic diploids are made by prevention of the extrusion of the secondary polocyte and the haploid embryo is made diploid by inhibition of the first cell division.This is typically done by a cold and pressure shock administered around the time of the prophase of the second meiotic and first mitotic division,respectively.All the while normal diploids with Japanese flounder sperm were also produced as controls.Normal diploids and two gynogenetic diploids were analyzed by unilocus 10 microsatellites loci.The result showed the parental genotypes were found to be heterozygous at 7 loci and heterozygous at 3 loci.6 genotypes were found in normal diploid,alleles were random combination from the parents and the types enriched.Genetic similarity indexes were 0.976 6 and 0.959 5 between female and progenies and among progeny individuals,respectively,which approached that of the inbred line.Two genotypes were found to be completely homozygous in mitotic gynogenetic double haploid.Genetic similarity indexes were 0.806 2 and 0.742 5 between female and progenies and among progeny individuals.Furthermore,mitotic gynogenetic doubled haploids were fully homozygous.Meiotic gynogenetic diploids with a high degree of genetic similarity were suitable for fixing traits of female.Mitotic gynogenetic doubled haploids with high homogeneity were suitable as clonal founders.Differently from meiotic gynogenesis diploidization is based on a prekaryogamic oocyte manipulation,in mitotic gynogenesis it is actually a postkaryogamic zygotic manipulation.The resulting mitotic gynogenetic double haploids are all homozygous but not clonal because they do not necessarily share the same alleles owing to variable chromosome segregation and genetic recombination during maternal gametogenesis.Each of them,however,can be a clonal founder capable of giving rise to an isoallelic clone,if reproduced gynogenetically.Although mitotic gynogenesis can achieve homozygote according one generation,but the survival rate of process in induction,incubation and maturation is relatively low,the establishment of clone is extremely difficult.Thus,scholars have proposed to improve the genetic similarity and fix the good traits of female with successive meiosisinduced methods.In view of distinct genetic characteristics in both diploids,as long as the successful induction,it can play an important role in fixing characters of female and clone production.Both kinds of gynogenesis can become high quality breeding materials or improved strains.