Ferris Kathleen G, Sexton Jason P, Willis John H
Department of Biology, Duke University, 125 Science Drive, Durham, NC 27708, USA
School of Natural Sciences, University of California Merced, 5200 North Lake Road, Merced, CA 95343, USA.
Philos Trans R Soc Lond B Biol Sci. 2014 Aug 5;369(1648). doi: 10.1098/rstb.2014.0001.
Speciation can occur on both large and small geographical scales. In plants, local speciation, where small populations split off from a large-ranged progenitor species, is thought to be the dominant mode, yet there are still few examples to verify speciation has occurred in this manner. A recently described morphological species in the yellow monkey flowers, Mimulus filicifolius, is an excellent candidate for local speciation because of its highly restricted geographical range. Mimulus filicifolius was formerly identified as a population of M. laciniatus due to similar lobed leaf morphology and rocky outcrop habitat. To investigate whether M. filicifolius is genetically divergent and reproductively isolated from M. laciniatus, we examined patterns of genetic diversity in ten nuclear and eight microsatellite loci, and hybrid fertility in M. filicifolius and its purported close relatives: M. laciniatus, M. guttatus and M. nasutus. We found that M. filicifolius is genetically divergent from the other species and strongly reproductively isolated from M. laciniatus. We conclude that M. filicifolius is an independent rock outcrop specialist despite being morphologically and ecologically similar to M. laciniatus, and that its small geographical range nested within other wide-ranging members of the M. guttatus species complex is consistent with local speciation.
物种形成可以在大的和小的地理尺度上发生。在植物中，局部物种形成，即小种群从大范围的祖先物种中分化出来，被认为是主要模式，但仍很少有例子能证实以这种方式发生了物种形成。最近描述的一种黄猴面花形态物种，丝状叶沟酸浆（Mimulus filicifolius），因其高度受限的地理范围，是局部物种形成的一个极佳候选对象。丝状叶沟酸浆以前因其叶形有裂片且栖息地为岩石露头，而被鉴定为裂叶沟酸浆（M. laciniatus）的一个种群。为了研究丝状叶沟酸浆在基因上是否与裂叶沟酸浆不同，以及在生殖上是否隔离，我们检测了十个核基因座和八个微卫星基因座的遗传多样性模式，以及丝状叶沟酸浆及其所谓的近缘种：裂叶沟酸浆、斑点沟酸浆（M. guttatus）和鼻状沟酸浆（M. nasutus）的杂交育性。我们发现丝状叶沟酸浆在基因上与其他物种不同，并且与裂叶沟酸浆在生殖上强烈隔离。我们得出结论，丝状叶沟酸浆是一种独立的岩石露头专性物种，尽管在形态和生态上与裂叶沟酸浆相似，而且它在斑点沟酸浆物种复合体其他分布广泛的成员中的小地理范围与局部物种形成是一致的。
