杉木地理种源的EST-SSR分子标记变异研究

研究采用EST-SSR分子标记对全国不同杉木种源区的42个代表性种源进行了地理种源分子标记的遗传多样性研究。实验结果表明,杉木种源水平上存在较高的遗传多态性。实验使用15个EST-SSR引物扩增出17个位点,共有52个多态性等位基因,每个位点平均具3.058 8个等位基因,平均每个座位的PIC为0.296。相对其他研究,该研究利用SSR标记在每位点检测到更多的遗传变异信息。以遗传距离10作为阀值时,42个杉木种源聚类分析可知,除了福建永春碧卿(编号2)和广西浦北(编号16)种源自成一类外,其他40个种源按从南到北、从东到西的地理分布被聚为四大类群,与以往的杉木种子区划研究结果有较高的吻合度。同时,研究也检测到SSR分子标记的等位基因频率在四大类群间存在着较大的变异,而且这些标记大多位于与植物抗逆性相关的功能基因的编码区域内。因此,笔者推测杉木的地理变异可能与这些基因的等位变异有关。

Variation of EST-SSR molecular markers among provenances of Chinese fir

In order to detect the genetic variation of Chinese fir provenance, 42 Chinese fir provenance samples were selected for genetic diversity analysis based on EST-SSR makers. Experimental results showed that there was higher genetic polymorphism among Chinese fir provenance. Base on the 17 locus amplified by the 15 EST-SSR pair primers, a total of 52 polymorphic alleles with average of 3.058 8 alleles for per locus were found. The average PIC was 0.296 for each locus. Comparing to others makers, more genetic variation information could be detected by SSR. Except provenance No. 2 and provenance No. 16, the other 40 provenances could be classified into four groups, with genetic distance of 10 as threshold. Our results fit well with the formal research on Chinese fir seed zones map based on growth and adaptive traits.In this study, we also found that there were some SSR variations located in the coding area of functional genes responding to certain biological or non-biological stress. The authors suggested that the geographic variation of Chinese fir might be due to these allelic variations of genes or in other words, the adaptive variation and local fixation.