团头鲂EST-SSR在厚颌鲂中的跨种扩增及杂交F_1的鉴定

Cross-species amplification of Megalobrama amblycephala EST-SSR in M.pellegrini and identification of their reciprocal hybrids

为了研究团头鲂微卫星引物在厚颌鲂中跨种扩增的适用性,并进行其杂交F1的鉴定,实验筛查了90个团头鲂EST-SSR位点在厚颌鲂中的扩增效果,同时选取了26对团头鲂与厚颌鲂微卫星引物对团头鲂自交子代、厚颌鲂自交子代及其正交和反交杂交F1共4个组合进行鉴定。结果显示,团头鲂90个微卫星位点中有76个(84.4%)在厚颌鲂中能够稳定扩增,随机选取50个位点在厚颌鲂30尾野生个体中扩增获得了13个多态性微卫星位点,平均等位基因数为3.2,平均观测杂合度为0.72,平均多态信息含量为0.42。通过10对团头鲂EST-SSR与16对厚颌鲂SSR引物在4个组合中扩增后发现,4个位点(MP01,MP03,MP24和MP26)在团头鲂自交子代中无扩增产物,2个位点(MA163和MA189)在厚颌鲂自交子代中无扩增产物,其余20个位点均能在4个组合中稳定扩增,其中9个位点可单独有效鉴定出团头鲂自交子代、厚颌鲂自交子代及包括正交和反交在内的杂交F1,其余位点可以通过组合鉴定出杂交F1。杂交F1中正交组合和反交组合无法通过本实验中的微卫星鉴别。

To investigate the applicability of microsatellite markers developed from Megalobrama amblycephala in M. pellegrini and find the molecular markers to identify the M. amblycephala, M. pellegrini and their reciprocal hybrids,90 pairs of M. amblycephala EST-SSR primers were synthesized for cross- species amplification on the genome DNA of M. pellegrini, and 26 pairs of microsatellite primers of M. amblycephala and M. pellegrini were screened for PCR amplification on the genome DNA of M. amblycephala,M, pellegrini and their reciprocal hybrids. The results revealed that 76 pairs （84.4%）of the primers were amplified successfully. Fifty pairs were screened from these 76 primers to test the polymorphism in M. pellegrini population and 13 markers were polymorphic with an average of 3.2 alleles per locus,the mean observed heterozygosity being 0.72 and the mean PIC being 0.42. The results of PCR amplification on the genome DNA of M. amblycephala, M. pellegrini and their reciprocal hybrids indicated that 4 primer pairs had no amplified products on M. amblycephala, and 2 primer pairs had no amplified products on M. pellegrini. Among the 20 loci which had effective amplified products, 9 specific loci could identify M. arnblycephala ,M. pellegrini and the reciprocal hybrids ,respectively. Combination of the other 17 specific loci also distinguished M. amblycephala, M. peUegrini and the reciprocal hybrids effectively. However, the reciprocal hybrids [ M. amblycephala （ ♀ ） x M. pellegrini （ ♂ ）, M. pellegrini （ 2 ） x M. amblycephala （ ♀ ） ] could not be identified through these markers used in this study.