施氏鲟精子诱导匙吻鲟雌核发育

Induction of meiotic gynogenesis in paddlefish (Polyodon spathula) using UV-irradiated Amur sturgeon (Acipenser schrenckii) sperm

采用照射强度为10188μW(/cm2·s),照射距离为15cm的紫外线对施氏鲟(Acipenser schrenckii)精子进行4-7min的照射,用照射后的精子对匙吻鲟(Polyodon spathula)卵进行人工授精,以探索精子的最佳紫外线照射时间。设计热休克起始时间、持续时间和休克温度3因子、3水平的正交试验,以探索人工诱导匙吻鲟雌核发育的理想热休克条件。结果表明:用紫外线照射5min处理的施氏鲟精子,与匙吻鲟卵受精所得胚胎经染色体观察均为单倍体(n=60),表明照射精子遗传失活的有效性和可靠性;若热休克处理前受精卵保持在(18±0.3)℃,在一定的休克温度(35-39℃)条件下,于不同时间(受精后16-20min)起始热休克,持续处理2min均能诱导受精卵染色体加倍。对热休克处理条件的优化结果表明,将受精卵于受精后18min,在37℃的水中热休克处理2min,二倍体诱导率最高,达18.8%。染色体鉴定显示,该条件下处理的胚胎均为二倍体(2n=120),未发现单倍体和非整倍体。本研究为进一步分析异源精子诱导匙吻鲟雌核发育机制以及匙吻鲟性别决定的分子机制奠定了基础。

Sperms of Amur sturgeon（ Acipenser schrenckii） were irradiated by UV light 15 cm away at the intensity of 10 188 μW/（cm2·s） for different time（4-7 min）. Then activated eggs of paddlefish（ Polyodon spathula） were fertilized by these sperms. The second polar body extrusion of fertilized egg was inhibited by heat shock for gynogenesis induction. The optimum conditions for retention of the second polar body in paddlefish were investigated by altering initiation time,temperature and duration of heat shock treatment.Chromosome ploidy was examined through chromosome identification method. The result showed that activated eggs were fertilized by sperms pre-treated with UV irradiation for 5 min and the embryo were haploid （n=60）, which approved the validity of UV irradiation. If the fertilized eggs were maintained at （18 ± 0.3）℃ before any treatment, chromosome doubling could be induced by heat shock under the temperature of 35-39℃ for 2 min after 16-20 min post-fertilization. Heat shock treatment under 37℃ for a 2 min duration after 18 min post-fertilization resulted in the highest diploid induction rate of 18.8%. Chromosome identification result revealed that embryos treated under the above conditions were all diploid embryos （2n=120）.This experiment provides basis for understanding the sex determination and feminization mechanism of gynogenesis induced by heterogenous sperms in paddlefish. [Journal of Fishery Sciences of China,2009,16 （5）： 728-735]