适于蛹虫草遗传多样性研究的线粒体分子标记的筛选

Determining mitochondrial molecular markers suitable for genetic diversity analysis of Cordyceps militaris

摘要:

摘要:【目的】从蛹虫草线粒体DNA中寻找适于遗传多样性研究的分子标记。【方法】通过PCR扩增和序列分析，比较了20个蛹虫草菌株在12个线粒体DNA片段和3个细胞核DNA片段上的序列变异。【结果】蛹虫草在线粒体DNA上的变异水平高于核DNA，主要表现为线粒体基因内含子的插入缺失多样性和较多的碱基变异位点。不同线粒体DNA片段的变异水平也有差异，而且内含子蛋白比外显子编码的蛋白质更易发生氨基酸的改变。增加使用的分子标记数目，其所揭示的遗传多样性程度也在逐渐提高。【结论】我们依 次推荐nad3-cox2、cox2-nad5、cox2、cox3、cob和cox1这6个线粒体DNA位点用于今后蛹虫草遗传多样性或群体遗传结构的分析。

Abstract:

Abstract:［Objective］To screen efficient molecular markers suitable for genetic diversity analysis of Cordyceps militaris from mitochondrial DNA.［Methods］We amplified 12 mitochondrial DNA fragments and 3 nuclear DNA fragments from each of 20 C. militaris isolates and analyzed nucleotide variations on these DNA fragments.［Results］We revealed a greatly higher genetic variation in mitochondrial DNA fragments than in nuclear DNA fragments． Specifically，C. militaris isolates exhibited intron presence/absence diversity in some mitochondrial fragments，and more variable sites were found in mitochondrial fragments than in nuclear fragments. The extent of nucleotide variations also varied by mitochondrial fragment，and intronic proteins seemed to be more vulnerable to amino acid changes than exonic proteins. Genetic diversity increased with the number of molecular markers used.［Conclusion］We recommended using (in order) nad3-cox2，cox2-nad5，cox2，cox3，cob，and cox1 for future genetic diversity and population genetic studies of C.militaris.