Department of Botany, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, 305-0005, Japan.
J Plant Res. 2009 Nov;122(6):585-95. doi: 10.1007/s10265-009-0254-4. Epub 2009 Jul 28.
Rheophilous Osmunda lancea often hybridizes with a dryland ally, Osmunda japonica, to produce O. x intermedia, forming zonation in riverbanks and the adjacent dryland along flooding frequency clines. This study examined the genetic structure of populations consisting of O. x intermedia and the two parental species by analyzing ten nuclear DNA markers [six cleaved amplified polymorphic sequence (CAPS) markers and three simple sequence repeat (SSR) markers developed from an expressed sequence tag (EST) library, and the sequence of the glyceraldehyde-3-phosphate dehydrogenase gene GapCp] and chloroplast DNA sequences. The results suggest that the nuclear genes of O. japonica and O. lancea are genetically differentiated despite shared polymorphism in their chloroplast DNA sequences. This discrepancy may be attributable to natural selection and recent introgression, although it is not evident if introgression occurs between O. japonica and O. lancea in the examined populations. Our findings of putative F2 hybrids in O. x intermedia support its partial reproducibility, and also suggest that formation of later-generation hybrids generates morphological variation in O. x intermedia. O. lancea plants collected from geographically distant localities were genetically very similar, and it is suggested that O. lancea originated monotopically.
嗜水亚洲金毛狗常与旱地亲缘种日本金毛狗杂交，产生 O. x intermedia，在洪水频率梯度的河岸和相邻旱地形成分带现象。本研究通过分析十个核 DNA 标记（六个来自表达序列标签 (EST) 文库的切割扩增多态性序列 (CAPS) 标记和三个简单序列重复 (SSR) 标记，以及甘油醛-3-磷酸脱氢酶基因 GapCp 的序列）和叶绿体 DNA 序列，研究了由 O. x intermedia 和两个亲本种组成的种群的遗传结构。结果表明，尽管它们的叶绿体 DNA 序列存在共享多态性，但 O. japonica 和 O. lancea 的核基因在遗传上是分化的。这种差异可能归因于自然选择和近期的基因渗入，但在研究的种群中，O. japonica 和 O. lancea 之间是否发生基因渗入尚不清楚。我们在 O. x intermedia 中发现的假定 F2 杂种的结果支持其部分可重复性，也表明后期杂种的形成在 O. x intermedia 中产生了形态变异。从地理上遥远的地方采集的 O. lancea 植物在遗传上非常相似，这表明 O. lancea 是单起源的。
