鲮微卫星DNA分子标记的筛选与遗传多样性分析

Screening of Microsatellite Molecular Markers and Genetic Diversity Analysis for Mud Carp

采用磁珠富集法对已建立的生长较快的西江段野生浅色鲮群体的极大、极小群体各31尾基因组DNA进行了微卫星序列的筛选,128个阳性克隆成功测序93个,其中80个为的微卫星序列,微卫星序列完美型占85%,非完美型占6.25%,混合型占8.75%。利用微卫星序列合成了23对微卫星引物,扩增结果表明,等位基因数为1～10个,扩增片段大小为92～283bp,其中14对引物扩增条带清晰,为中度或高度多态位点,极大、极小群体的平均有效等位基因数和平均多态信息含量分别为3.0784、3.2079和0.5675、0.5974,反映出2个群体遗传多样性均较丰富;高度多态性引物4的位点b,片段大小为119bp,在极大群体中出现频率为61.3%,在极小群体占22.6%,出现频率极大群体高于极小群体近3倍,初步可作为候选差异性分子标记。

In this study, DNA templates were from min and max groups of wild light color mud carp, Cirrhinus molitorella from Xi Jiang population, and 31 individuals＇ from each group （min and max） were used to isolate the microsatellite DNA using magnetic bead hybridization method. Among 93 clones successfully sequenced from 128 positive clones, 80 microsatellites were found, in which 85% were perfect with 6.25% imperfect type and 8.75% compound type. 23 pairs of primers were designed and composed. 1 to 10 alleles were detected at each locus and the range of fragment length was 92-283 bp, in which amplified bands from 14 pairs of primers were clear. All of them have moderate or high polymorphism. The average number of effective alleles and the average polymorphism information content, PIC of the two groups were 3.078 4, 3.207 9 and 0.567 5, 0.597 4 respectively. Both of the two groups have abundant genetic polymorphism according to the average PIC. The appearance frequencies of highly polymorphic primer 4＇s of locus b were 61.3%, and 22.6% respectively in max and mini group, and the fragment length of the locus was 119 bp. The frequency in the max group was nearly 3 times higher than that in the mini, indicating that this locus may be potential candidate for differential molecular markers.