Phylogenetic and Geographic Patterns in the Diversity of Peatmosses(Sphagnum)

0075611肖氏泥炭藓（泥炭藓属植物）是许多北方和南半球生态系统的主要组成部分。泥炭地占主导地位的栖息地在区域水文方面具有重要的生态意义，泥炭积累对全球碳收支和全球气候具有深远的意义。以泥炭藓为主的泥炭地在北方地区最为突出，那里堆积着大量的部分分解的泥炭，大多数人将泥炭藓与这种北方的栖息地联系在一起。尽管如此，泥炭藓的物种在热带地区也是多样化的，一种进化假说认为南美洲是泥炭多样性的中心。杜克大学的乔纳森·肖博士和他的同事们正在研究200-450种泥炭藓的分类学和系统发育多样性，以调查这些和其他关于全世界该属物种多样性模式的想法。该项目广泛使用DNA测序，核和叶绿体基因，作为证据的来源系统发育（系谱）相关性，并估计水平的遗传和基因组多样性的亚系泥炭藓。分子和形态学的证据线将结合在杂交和神秘物种的假定情况下，在那里相似的形态被认为掩盖了显着的遗传分歧的研究。该项目将改进全世界泥炭藓数百个物种的属下分类，并有助于了解地质时期泥炭质多样化的机制。

0075611Shaw Peatmosses (plants of the bryophyte genus Sphagnum) are a dominant component of many Northern and Southern Hemisphere ecosystems. Sphagnum-dominated habitats are ecologically important in terms of regional hydrology, and peat accumulation is of profound significance to global carbon budgets and therefore global climates. Sphagnum-dominated peatlands are most prominent in boreal regions where huge deposits of partially decomposed peat accumulate, and most people associate Sphagnum with such northern hemisphere habitats. Nonetheless, species of Sphagnum are also diverse in the tropics, and one evolutionary hypothesis suggests that South America is the center of peatmoss diversity. Dr. Jonathan Shaw of Duke University and colleagues are studying the taxonomic and phylogenetic diversity of the 200-450 species of Sphagnum in order to investigate these and other ideas about the patterns of species diversity worldwide in the genus. The project makes extensive use of DNA sequencing, of both nuclear and chloroplast genes, as sources of evidence of phylogenetic (genealogical) relatedness and to estimate levels of genetic and genomic diversity within sublineages of Sphagnum. Molecular and morphological lines of evidence will be combined in studies of presumptive cases of hybridization and of cryptic species, where similar morphologies are thought to obscure significant genetic divergence. The project will lead to an improved infrageneric classification for the hundreds of species worldwide of Sphagnum, and contribute to understanding the mechanisms of peatmoss diversification over geological time.