Gunnarsson U, Shaw A J, Lönn M
Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
Mol Ecol. 2007 Jan;16(2):305-12. doi: 10.1111/j.1365-294X.2006.03144.x.
Sphagnum (peatmoss) dominates huge areas of the Northern Hemisphere and acts as a significant carbon sink on a global scale, yet little is known about the genetic structure of Sphagnum populations. We investigated genetic structure within a population of the common peatmoss Sphagnum fuscum, to assess local patterns of genetic diversity and the spatial extent of clones. One hundred seventeen shoots were sampled from five transects in Fuglmyra, central Norway, and sequenced for three anonymous DNA regions. Five neighbourhood patches were marked along each transect, and from each patch, five stems were sampled for molecular analyses. Seventeen haplotypes could be distinguished and two major groups of haplotypes differed by 12 mutational steps. The two major haplotype groups differed significantly in microhabitat association along the distance to groundwater table and the pH gradients, indicating microhabitat differentiation. The haplotypes within these groups were all genetically similar, differing by one or two mutations. The most common haplotype occurred in four transects separated by 250-m distance. Most of the molecular variation in the population was found among transects, and within patches. Large dominating clones within each transect resulted in low variation explained by the among-patch-within-transect component of spatial structure. Mutation appears to account for a larger proportion of the population variation than recombination. Within the population, vegetative growth and asexual reproduction from gametophyte fragments dominate as the main reproductive mode.
泥炭藓在北半球大片区域占据主导地位，在全球范围内是重要的碳汇，但人们对泥炭藓种群的遗传结构知之甚少。我们调查了常见泥炭藓Sphagnum fuscum种群内的遗传结构，以评估当地的遗传多样性模式和克隆的空间范围。从挪威中部富尔米拉的五个样带采集了117个枝条，并对三个匿名DNA区域进行了测序。沿着每个样带标记了五个邻域斑块，从每个斑块中采集五个茎进行分子分析。可以区分出17种单倍型，两个主要的单倍型组相差12个突变步骤。这两个主要的单倍型组在沿地下水位距离和pH梯度的微生境关联上有显著差异，表明存在微生境分化。这些组内的单倍型在遗传上都很相似，相差一两个突变。最常见的单倍型出现在相距250米的四个样带中。种群中的大部分分子变异存在于样带之间和斑块内部。每个样带内大型占主导地位的克隆导致由样带内斑块间空间结构成分解释的变异较低。突变似乎在种群变异中所占比例比重组更大。在种群内部，配子体片段的营养生长和无性繁殖作为主要繁殖方式占主导地位。
