Department of Botany, Swedish Museum of Natural History, Stockholm, Sweden.
PLoS One. 2013 Jun 14;8(6):e65576. doi: 10.1371/journal.pone.0065576. Print 2013.
Establishing the dates for the origin and main diversification events in the phylogeny of Ascomycota is among the most crucial remaining goals in understanding the evolution of Fungi. There have been several analyses of divergence times in the fungal tree of life in the last two decades, but most have yielded contrasting results for the origin of the major lineages. Moreover, very few studies have provided temporal estimates for a large set of clades within Ascomycota. We performed molecular dating to estimate the divergence times of most of the major groups of Ascomycota. To account for paleontological uncertainty, we included alternative fossil constraints as different scenarios to enable a discussion of the effect of selection of fossils. We used data from 6 molecular markers and 121 extant taxa within Ascomycota. Our various 'relaxed clock' scenarios suggest that the origin and diversification of the Pezizomycotina occurred in the Cambrian. The main lineages of lichen-forming Ascomycota originated at least as early as the Carboniferous, with successive radiations in the Jurassic and Cretaceous generating the diversity of the main modern groups. Our study provides new information about the timing of the main diversification events in Ascomycota, including estimates for classes, orders and families of both lichenized and non-lichenized Ascomycota, many of which had not been previously dated.
确定子囊菌系统发育中起源和主要多样化事件的日期是理解真菌进化的最关键目标之一。在过去的二十年中，已经有几项关于真菌生命树分歧时间的分析，但大多数分析对主要谱系的起源得出了相互矛盾的结果。此外，很少有研究为子囊菌中的大量类群提供了时间估计。我们进行了分子定年来估计大多数子囊菌主要类群的分歧时间。为了考虑古生物学的不确定性，我们将替代化石约束作为不同的场景包含在内，以讨论选择化石的影响。我们使用了来自 6 个分子标记和 121 个现存子囊菌类群的数据。我们的各种“松弛时钟”情景表明，散囊菌的起源和多样化发生在寒武纪。地衣形成子囊菌的主要谱系至少起源于石炭纪，随后在侏罗纪和白垩纪的辐射产生了现代主要群体的多样性。我们的研究提供了关于子囊菌主要多样化事件时间的新信息，包括对地衣和非地衣子囊菌的纲、目和科的估计，其中许多以前没有被确定过日期。
