异源精子诱导牙鲆雌核发育二倍体

Gynogenesis Induced by Heterogenous Sperms and Cold Shock in Olive Flounder Paralichthys olivaceus

采用紫外线照射处理的石鲽精子和受精后冷休克的方法诱导了牙鲆雌核发育.结果表明:用2只平行的相距15cm的20W紫外灯管,照射距离为10cm,在5～100s时间范围内照射石鲽精子时,受精卵的发育表现了典型的哈特维希效应,照射40s的精子所得胚胎的孵化率达到最高峰(41%),染色体观察结果显示,此照射剂量组的所有胚胎均为单倍体(n=24),表明照射精子遗传失活的有效性和可靠性.如果冷休克处理前受精卵保持在(15.5±0.5)℃,受精卵在一定的休克温度(0～10℃)条件下,用不同休克起始时间(受精后1～10min)及冷休克处理持续时间(15～90min)均能诱导染色体加倍.对冷休克处理条件的优化结果表明,在2～4℃条件下,受精后3min开始、冷休克处理45min时,二倍体诱导率最高,达79.7%.染色体鉴定显示,处理组的正常胚胎均为二倍体(2n=48),未发现单倍体和非整倍体.

Meiotic gynogenesis in olive flounder Paralichthys olivaceus was induced by UV irradiated heterogenous sperms from stone flounder Kareius bicoloratus and cold shocks. Using 2 parallel UV lights （20W each）, when the distance between the sperms and the UV lights was 10cm, the developmental potential of the gynogenetic haploids obtained from 5-100s irradiation exhibited a typical “Hertwig Effect”. The optimal time of UV irradiation for effective inactivation of stone flounder sperms was 40sec. The haploid chromosome number of embryos in this group indicated the effectiveness of UV irradiation. When the fertilized eggs were maintained at （15 ± 0.5）℃ before any treatment, chromosome diploidy was achieved by early cold shocks applied 1-10min after fertilization at 0 - 10℃ for 15- 90min durations. For obtaining the maximal rate of diploidy in this species （79.7 %） the optimal cold shock was at 2 -4℃, applied 3min after fertilization and continued for 45min. All putative diploid gynogens induced by this condition showed a diploid number of 48 chromosomes. More than 5000 diploid gynogens were obtained.