扇贝异源四倍体诱导后代的细胞遗传学研究

Cytogenetic analysis of the offspring from aliotetraploid induction of scallop(Chlamys farreri ♀)×(Patinopecten yessoensis(?))

采用50mg/L 6-二甲氨基嘌呤(6-DMAP)处理15min 抑制栉孔扇贝(Chlamys farreri♀)×虾夷扇贝(Patinopecten yessoensis)异源受精卵第一极体的释放诱导扇贝异源四倍体。采用基因组荧光原位杂交技术(GISH)结合染色体滴片技术对扇贝异源四倍体诱导后代的染色体遗传构成进行研究,对授精后17～66h 内6个时间段各300多个分裂相进行统计分析。结果表明,诱导异源四倍体过程中产生了多种倍性的幼虫,包括5.192%的四倍体、16.577%的三倍体以及单倍体、二倍体、五倍体和大量的非整倍体。在17～66h内同一组染色体数,所占比率并未出现随着取样时间的变化而发生明显上升或下降的趋势。在染色体构成上,诱导后代都分别继承了双亲的染色体,除正常杂交产生的异源二倍体外均为非对称性继承。GISH 鉴定结果表明本实验所诱导的四倍体为真正的异源四倍体,同时也说明两套异源染色体具有较强的亲和性。在诱导后代中还出现了较小比例的染色体不完全继承个体。对产生这些现象的可能原因进行了探讨。

Artificial allotetraploids of scallop were induced using sperm from Patinopecten yessoensis and eggs from Chlamys farreri. The induction was attempted by blocking the release of the first polar body （PB1） in the fertilized eggs with 6- dimethylaminopurine （50mg/L）. The genomic constitution and its variation in larvae at six periods from induced offspring of allotetmploid were studied by genome in situ hybridization （GISH） and traditional chromosome preparation techniques. The results show that 5. 192% allotetraploids and large proportion of aneuploids and allotriploids are obtained. The unequal and ruleless chromosome contributions are observed except the allediploid. Allediploid inherites one set of chromosome from each side of the parents. But others do not inherit euploidy sets of chromosomes from the parents. These resuhs may suggest that the two sets of chromosomes from the two scallop species have great compatibility in the zygotes. There are also some incomplete-inherited individuals in the offspring. In addition, the possible causes of producing these phenomena are discussed in this paper.