【摘要】 研究了利用6-二甲基氨基嘌呤(60μg/mL;6-DMAP)抑制第1卵裂诱导栉孔扇贝[Chlamys farreri(Jones et Pre-ston)]雄核发育二倍体的条件。雄核发育单倍体是将强度为2.8 mW/(cm2.s)的紫外线照射20 s的卵子与正常精子受精后得到的。6-DMAP不仅可以有效地抑制减数分裂,还可以有效地抑制有丝分裂;抑制第1卵裂的适宜起始时间为受精后80 min,诱导率为21.0%~22.6%。细胞学观察显示,6-DMAP抑制第1卵裂产生的雄核发育二倍体主要来源于第1卵裂中期的受精卵,由于阻止了染色体分离和原核移动,导致一个融合的二倍性雌性原核的形成;经紫外线照射的卵核在第1卵裂中期没能形成染色体,而是形成1个浓缩的染色质小体,没有参与第1卵裂后期的核分裂。尽管倍化率和D形幼虫发生率较低,但本研究证实了栉孔扇贝雄核发育二倍体人工诱导的可行性。[中国水产科学,2006,13(4):585-590]更多还原

【Abstract】 Androgenesis,development from paternal but not maternal chromosomes,can be used in numerous genetic studies and breeding programs,including rapid establishment of isogenic,clonal lines,sex control,generation of nucleo-cytoplasmic hybrids between two different species,and recovery of valuable strains from cryopreserved sperm.In numerous fish species,efficient procedures for genetic inactivation of eggs and restoring diploidy have been studied and successful diploid androgenesis have been produced.However,in mollusks artificial induction of androgenetic diploids has been not documented.In this study,conditions required for the induction of androgenetic diploids by suppression of first cleavage in the Zhikong scallop Chlamys farreri（Jones et Preston） were examined using treatments of 6-dimethylaminopurine（60?μg/mL;6-DMAP）.Haploid androgenesis was induced by eggs which were ultraviolet（UV）-irradiated for 20 s at an intensity of 2.8?mW/(cm²·s). Treatment with 6-DMAP was effective in inhibiting not only meiosis but also mitosis,and the optimum time for the suppression of first cleavage began 80?min after insemination,resulting in 21.0%-22.6% androgenetic diploids.Cytological observations indicated that 6-DMAP disrupted the spindle at mitosis and inhibited chromosome movement,resulting in the formation of one diploid female nucleus.At metaphase of the first cleavage,the UV-irradiated female nucleus did not form chromosome,but became a dense chromatin body（DCB）,which did not participate in the karyokinesis at anaphase of the first cleavage.Although attempts to produce androgenetic diploids demonstrated that ploidy levels and the developmental rate of D-shaped larvae are low,the results of this study suggest the possibility of producing androgenetic diploids in C.farreri（Jones et Preston）.更多还原