Centro Regional Universitario Bariloche-Universidad Nacional del Comahue, INIBIOMA-CONICET, Bariloche, Argentina.
Mol Phylogenet Evol. 2010 Jan;54(1):235-42. doi: 10.1016/j.ympev.2009.08.008. Epub 2009 Aug 14.
Subgenus Nothofagus, although geographically restricted at present to temperate areas of South America, has captured much attention in discussions of plant biogeography due to its widespread distribution through Gondwanan continents during the Tertiary. However, phylogenetic relationships within the subgenus Nothofagus have not yet been resolved. We examined geographic patterns of intraspecific and interspecific genetic variation to detect whether incongruences in nuclear or plastid DNA phylogenies occur, in order to better understand the evolutionary history of the subgenus Nothofagus. We conducted spatially-explicit sampling at 10 distinct locations throughout the range of austral South American forests and sampled all present Nothofagus species. We used ITS and chloroplast DNA sequences to estimate phylogenetic relationships. A phylogeny constructed from nuclear genes resolved the subgenus Nothofagus as monophyletic. We found that N. antarctica was a sister to a clade of evergreen species (N. betuloides, N. dombeyi, and N. nitida), while N. pumilio likely diverged earlier. Nine cpDNA haplotypes were distinguished in the subgenus Nothofagus which were associated to geographic locations rather than to taxonomic relationships. This species-independent cpDNA phylogeographic structures within the subgenus Nothofagus may be related to repeated chloroplast capture events over geological time in Patagonia.
虽然目前的地理分布范围仅限于南美洲的温带地区，但由于在第三纪期间在冈瓦纳大陆广泛分布，山龙眼亚属在植物生物地理学的讨论中引起了广泛关注。然而，山龙眼亚属内的系统发育关系尚未得到解决。我们检查了种内和种间遗传变异的地理模式，以检测核或质体 DNA 系统发育是否存在不一致，以便更好地了解山龙眼亚属的进化历史。我们在南美的南部森林范围内的 10 个不同地点进行了空间明确的采样，并采样了所有现存的山龙眼物种。我们使用 ITS 和叶绿体 DNA 序列来估计系统发育关系。从核基因构建的系统发育将山龙眼亚属解析为单系。我们发现，南极山龙眼与一个常绿物种（山龙眼、山龙眼和山龙眼）的分支是姐妹关系，而山龙眼可能更早分化。在山龙眼亚属中区分出了 9 种叶绿体单倍型，它们与地理位置有关，而与分类关系无关。这种与物种无关的山龙眼亚属内的叶绿体系统地理学结构可能与在巴塔哥尼亚的地质时间内发生的多次叶绿体捕获事件有关。
