High genetic diversity in a rare and endangered sunflower as compared to a common congener
High genetic diversity in a rare and endangered sunflower as compared to a common congener
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DOI：
10.1111/j.1365-294x.2006.02937.x
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发表时间：
2006-08-01
影响因子：
4.9
通讯作者：
McCauley, D. E.
中科院分区：
文献类型：
--
作者：
Ellis, J. R.;Pashley, C. H.;McCauley, D. E.
在规划适当的保护策略时，确定孤立或碎片化物种的遗传结构至关重要。在这项研究中，我们利用核和叶绿体SSR(简单序列重复序列)来研究一种极其稀有的向日葵的群体遗传学，这种向日葵在北美只有三个地点已知。我们利用核SSR和叶绿体SSR研究了向日葵的遗传多样性水平和种群结构，并与更常见的同源向日葵进行了比较。我们还研究了它与罗汉果和狭叶向日葵的杂交起源。22个起源于栽培向日葵的核SSR。利用表达序列标签(EST)数据库，并已知可转移到轮纹夜蛾及其可能的亲本分类群，从而允许在群体遗传分析中对座位特异性效应进行统计控制。尽管数量稀少，但在核基因座和等量的叶绿体多样性水平上，轮叶轮藻的遗传多样性水平显著高于狭叶轮藻。黑线姬鼠的种群分裂水平较高，但与狭叶红鱼的种群分裂程度相当。对多位点基因分型的检测也显示克隆性传播具有高度的局部性。最后，我们得出结论，轮纹夜蛾不是杂交起源的，因为它在核基因座上没有表现出亲本等位基因的混合，并且它与其推测的亲本中的任何一个都不共享叶绿体DNA单倍型。
Determining the genetic structure of isolated or fragmented species is of critical importance when planning a suitable conservation strategy. In this study, we use nuclear and chloroplast SSRs (simple sequence repeats) to investigate the population genetics of an extremely rare sunflower, Helianthus verticillatus Small, which is known from only three locations in North America. We investigated levels of genetic diversity and population structure compared to a more common congener, Helianthus angustifolius L., using both nuclear and chloroplast SSRs. We also investigated its proposed hybrid origin from Helianthus grosseserratus Martens and H. angustifolius. Twenty- two nuclear SSRs originating from the cultivated sunflower (Helianthus annuus L.) expressed sequence tag (EST) database, and known to be transferable to H. verticillatus and its putative parental taxa, were used in this study thereby allowing for statistical control of locus-specific effects in population genetic analyses. Despite its rarity, H. verticillatus possessed significantly higher levels of genetic diversity than H. angustifolius at nuclear loci and equivalent levels of chloroplast diversity. Significant levels of population subdivision were observed in H. verticillatus but of a magnitude comparable to that of H. angustifolius. Inspection of multilocus genotypes also revealed that clonal spread is highly localized. Finally, we conclude that H. verticillatus is not of hybrid origin as it does not exhibit a mixture of parental alleles at nuclear loci, and it does not share a chloroplast DNA haplotype with either of its putative parents.