Science & Education, The Field Museum, Chicago, IL, USA; Biological Sciences, Ecology and Evolution, University of Illinois at Chicago, Chicago, IL, USA.
Biological Sciences, Depaul University, Chicago, IL, USA.
Mol Phylogenet Evol. 2018 Sep;126:58-73. doi: 10.1016/j.ympev.2018.04.006. Epub 2018 Apr 12.
A major challenge to evolutionary biologists is to understand how biodiversity is distributed through space and time and across the tree of life. Diversification of organisms is influenced by many factors that act at different times and geographic locations but it is still not clear which have a significant impact and how drivers interact. To study diversification, we chose the lichen genus Sticta, by sampling through most of the global range and producing a time tree. We estimate that Sticta originated about 30 million years ago, but biogoegraphic analysis was unclear in estimating the origin of the genus. Furthermore, we investigated the effect of dispersal ability finding that Sticta has a high dispersal rate, as collections from Hawaii showed that divergent lineages colonized the islands at least four times. Symbiont interactions were investigated using BiSSE to understand if green-algal or cyanobacterial symbiont interactions influenced diversification, only to find that the positive results were driven almost completely by Type I error. On the other hand, another BiSSE analysis found that an association with Andean tectonic activity increases the speciation rate of species.
进化生物学家面临的一个主要挑战是理解生物多样性如何在空间和时间上以及在整个生命之树上分布。生物多样性的多样化受到许多因素的影响，这些因素在不同的时间和地理位置起作用，但目前仍不清楚哪些因素具有重大影响以及驱动因素如何相互作用。为了研究多样化，我们选择了地衣属 Sticta，通过在全球大部分地区进行采样并生成时间树来进行研究。我们估计 Sticta 起源于大约 3000 万年前，但生物地理学分析在估计属的起源时并不清楚。此外，我们还研究了扩散能力的影响，发现 Sticta 的扩散率很高，因为来自夏威夷的采集表明，不同的谱系至少四次殖民了这些岛屿。我们使用 BiSSE 来研究共生体相互作用是否影响了多样化，结果发现只有绿色藻类或蓝细菌共生体相互作用的积极结果几乎完全是由 I 型错误驱动的。另一方面，另一个 BiSSE 分析发现，与安第斯构造活动的关联增加了物种的形成速度。
