Artificial gynogenesis in Cynoglossus semilaevis with homologous sperm and its verification using microsatellite markers

Effective methods for induction of gynogenetic diploids in Cynoglossus semilaevis are needed to initiate monosex culture. An effective protocol to induce half-smooth tongue sole gynogenesis using homologous sperm was developed in this study. A UV dose of 50 mJ cm-2 was found to be the most effective for genetic inactivation of tongue sole sperm. Treatment optima for cold shocks were 5 degrees C for 20-23 min at 5 min after fertilization and the hatching rate of gynogenetic diploids was 10.0%. Microsatellite analysis at locus Csou 6 revealed that there was no genetic contribution from the paternal genome in 24 progenies of a meiotic gynogenetic family. Polymerase chain reaction demonstrated that only four individuals of 24 meiotic gynogenetic diploids produced the female-specific band of about 205 bp. The female/male ratio of gynogenetic diploids was significantly different from the theoretical ratio of 1:1. It is possible that there are some recessive lethal genes in W chromosome.