Dated molecular phylogenies indicate a Miocene origin for Arabidopsis thaliana
Dated molecular phylogenies indicate a Miocene origin for Arabidopsis thaliana
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DOI：
10.1073/pnas.0909766107
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发表时间：
2010-10-26
影响因子：
11.1
通讯作者：
Mathews, Sarah
中科院分区：
文献类型：
--
作者：
Beilstein, Mark A.;Nagalingum, Nathalie S.;Mathews, Sarah
过时的分子系统学是理解物种多样性和将多样化速度的变化与历史事件联系起来的基础，这些历史事件包括发育途径的重组、基因组翻倍或扩散到新大陆。有效的化石校准点对于准确估计分化日期是必不可少的，但对于许多开花植物组来说，化石证据是不可用的或有限的。拟南芥是植物生物学中的主要遗传模式，也是第一个完成全基因组测序的植物，它属于十字花科植物。因此，拟南芥的进化时间及其基因组的历史一直存在争议。我们利用以前被忽视的化石证据来处理这些问题，发现拟南芥和拟南芥之间的分裂发生在13Mya左右，而拟南芥和油菜复合体(西兰花、甘蓝、油菜)之间的分裂发生在43Mya左右。这些估计比以前的估计早两到三倍，表明基因、基因组和发育进化的速度比先前假设的要慢得多，拟南芥是在变暖而不是降温的时期进化的。我们发现，十字花科与其姊妹科的分支物种多样性比率发生了2到10倍的变化。这一转变的时机表明，白垩纪-古近纪的大规模灭绝可能对它们的辐射产生了影响，油菜目蝴蝶与专门产芥末油植物的皮纹蝶共同多样化。
Dated molecular phylogenies are the basis for understanding species diversity and for linking changes in rates of diversification with historical events such as restructuring in developmental pathways, genome doubling, or dispersal onto a new continent. Valid fossil calibration points are essential to the accurate estimation of divergence dates, but for many groups of flowering plants fossil evidence is unavailable or limited. Arabidopsis thaliana, the primary genetic model in plant biology and the first plant to have its entire genome sequenced, belongs to one such group, the plant family Brassicaceae. Thus, the timing of A. thaliana evolution and the history of its genome have been controversial. We bring previously overlooked fossil evidence to bear on these questions and find the split between A. thaliana and Arabidopsis lyrata occurred about 13 Mya, and that the split between Arabidopsis and the Brassica complex (broccoli, cabbage, canola) occurred about 43 Mya. These estimates, which are two-to threefold older than previous estimates, indicate that gene, genomic, and developmental evolution occurred much more slowly than previously hypothesized and that Arabidopsis evolved during a period of warming rather than of cooling. We detected a 2-to 10-fold shift in species diversification rates on the branch uniting Brassicaceae with its sister families. The timing of this shift suggests a possible impact of the Cretaceous-Paleogene mass extinction on their radiation and that Brassicales codiversified with pierid butterflies that specialize on mustard-oil-producing plants.