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

Abstract

E¡ective methods for induction of gynogenetic diploids in Cynoglossus semilaevis are needed to initiate monosex culture. An e¡ective protocol to induce half-smooth tongue sole gynogenesis using homologous sperm was developed in this study. A UV dose of 50 mJ cm À 2 was found to be the most e¡ective for genetic inactivation of tongue sole sperm. Treatment optima for cold shocks were 5 1C 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-speci¢c band of about 205 bp. The female/ male ratio of gynogenetic diploids was signi¢cantly di¡erent from the theoretical ratio of 1:1. It is possible that there are some recessive lethal genes in W chromosome.

Meiotic gynogenesis with heterologous sperm in the mandarin fish Siniperca chuatsi and evidence for female homogamety

“…Gynogenesis has been considered as a powerful approach to study sex determination type, producing all‐female stock and developing pure lineages in fish. Artificial gynogenesis has been reported in many freshwater fish and some marine fish species with gynogenetic diploids successfully produced and/or cultured until maturation (Devlin & Nagahama, ; Ji et al, ; Xu et al, ). An optimal combination of temperature, duration and initiation time is critical for the cold shock treatment since even small variations may result in remarkable changes in the number of gynogenetic diploids obtained (Chen et al, ).…”

“…In general, the efficiency of the gynogenetic diploid production induced by homologous or heterologous sperm seems different from species to species. For example,Chen et al () and Ji et al () obtained a diploid gynogenetic rate of about 2.8% and 10.0% in C. semilaevis when induced by heterologous and homologous sperm respectively. Luckenbach et al () found that the diploid gynogenetic rate in Paralichthys lethostigma induced by homologous sperm was 2.1%, while the rate reached 1.6%–11.4% induced by heterogeneous sperm of Mugil cephalus .…”

Induction of meiotic gynogenesis in bagrid catfish (Pseudobagrus ussuriensis) with homologous sperm and its confirmation for female homogamety

“…The polymorphic molecular markers such as AFLP and SSR can help to solve these problems by identifying the maternal genetic characteristics (Dan, Mei, Wang & Gui, ; Zou, Wei & Pan, ). Utilization of heterologous sperm, especially with a different chromosome number, does not truly fertilize eggs for producing hybrids between distantly related species, ensuring that surviving larvae are indeed gynogens as the hybrids either showed a morphological marker or are absolutely lethal (Rothbard et al., ), but the fertilization rate and the diploid induction rate are lower than that induced by homologous sperm (Chen et al., ; Ji et al., ).…”

“…The entire process was carried out in the dark to prevent genetic photoreactivation (Hassanzadeh Saber & Hallajian, ). The rates of fertilization, hatching and larvae surviving were respectively determined as in the previous description (Ji et al., ; You et al., ). A maximum UV irradiation dosage with high sperm motility alone was used for the next experiments (Christopher et al., ).…”

“…The combination of artificial gynogenesis and sex reversal is an important approach to obtaining monosex stock in aquaculture. Using this strategy, monosex strains have been developed in many fish species, such as black carp ( Mylopharyngodon piceus ) (Rothbard et al., ), crucian carp ( Carassius cuvieri ) (Luo et al., ), half‐smooth tongue sole ( Cynoglossus semilaevis ) (Chen et al., ; Ji et al., ), yellow catfish ( Pelteobagrus fulvidraco ) (Liu et al., ), tilapia ( Oreochromis niloticus ) (Mair et al., ) and turbot ( Scophthalmus maximus) (Meng et al., ) and so on.…”