Assessment of Homozygosity in Gynogenetic Diploid Using Microsatellite Markers in Japanese Flounder (Paralichthys olivaceus)

Gynogenesis was thought to be a useful method to generate inbred lines in fish. In this study, analysis of 5-8 heterozygous loci in Japanese flounder (Paralichthys olivaceus) was used to measure the increment of homozygosity in meiogynogenetic diploid (Meiotic-A & Meiotic-B) and mitogynogenetic diploid (Mitotic-A). The result showed all homozygosity in Mitotic-G1, while a high percentage of heterozygosity in Meiosis-A and Meiosis-B except Poli11TUF. The rate of heterozygosity in meiogynogenetic progenies at the locus of Poli9TUF, Poli9-8TUF, Poli11TUF, Poli13TUF, Poli23TUF, Poli30TUF, Poli123TUF and Poli130TUF were 1.000 0, 1.000 0, 0.194 4, 0.945 9, 0.861 1, 1.000 0, 0.777 8 and 0.800 0, respectively. The average recombination rate of these eight loci is 0.822 4. The high proportion of heterozygotes for seven loci demonstrates that it is not a practical method for producing homozygous inbred lines in the gynogenetic fish produced by retention the second polar body; and treatments of suppressing the first cell division were more promising for this purpose.