39种桉树微卫星序列的遗传多样性分析

Microsatellites Analysis on the Genetic Diversity of 39 Eucalyptus Species

为进一步研究桉树微卫星跨种的相似性及长度多态性,从基因组DNA遗传变异的角度探讨各个桉树种间的遗传多态性程度,本研究选用2个扩增结果稳定,微卫星完整的SSR位点进行PCR产物直接测序,从DNA序列的层次上对39种桉树进行遗传多样性分析和微卫星多态性分析。从SSR位点的层次上进行遗传多样性分析发现,2个SSR位点Nei's遗传多样性指数Hs平均为0.576,期望杂合度He平均为0.736,多态信息含量PIC平均为0.694,位点e SSR-GR124遗传多样性较高,位点g SSR-CA013序列相对更为保守。基于微卫星序列和侧翼保守序列的比对分析,微卫星重复次数的变化可能与属内各亚属间的分类相关性较大,微卫星序列的碱基替换可能与属间分类的相关性更大。由2个位点的综合序列进行相似性比较和系统发育树分析发现,位点e SSR-GR124和位点g SSR-CA013能够作为伞房属和桉属属间分类鉴定的依据。

For further research is needed to study the homologous and length polymorphism of interspecies in Eucalyptus microsatellite, from the perspective of genomic DNA genetic variation to explore the degree of genetic polymorphism among Eucalyptus species. The study presented 2 SSR primer pairs which have a steady product and complete microsatellites to DNA sequencing. From the level of SSR loci to analysis the genetic diversity,average Nei＇s genetic diversity index Hs=0.576, average expected heterozygosity He=0.736, polymorphism information content PIC=0.694. Apparently, the paramenters of e SSR-GR124 locus were higher and the sequences of g SSR-CA013 locus were more conservative. The results of microsatellite and flanking region sequences found that the variety of microsatellite repeats were correlation with the taxonomy of subgenus, and the DNA base substitution were more relevant to the classification of genus. The study of the similarity comparison and the phylogenetic tree were indicate that the SSR Locus of e SSR-GR124 and g SSR-CA013 can be the classification basis for genus Corymbia and genus Eucalyptus.