Plants with double genomes might have had a better chance to survive the Cretaceous-Tertiary extinction event
Plants with double genomes might have had a better chance to survive the Cretaceous-Tertiary extinction event
复制标题
DOI：
10.1073/pnas.0900906106
复制
发表时间：
2009-04-07
影响因子：
11.1
通讯作者：
Van de Peer, Yves
中科院分区：
文献类型：
--
作者：
Fawcett, Jeffrey A.;Maere, Steven;Van de Peer, Yves
大多数开花植物都是古老的多倍体，在进化的早期经历了一次或多次全基因组复制。此外，许多不同的植物谱系似乎经历了额外的，更近的基因组复制。从旁系同源基因位于重复的片段或确定在大型表达序列标签集合，我们通过惩罚似然系统发育树推断这些最年轻的重复事件。我们发现，大多数这些独立的基因组重复在时间上是聚类的，似乎与第三纪（KT）的边界相吻合。KT灭绝事件是由一个或多个灾难性事件（如大规模小行星撞击和/或火山活动增加）引起的最近一次大规模灭绝。这些事件被认为产生了全球野火和尘埃云，在很长一段时间内切断了阳光，导致大约60%的植物物种灭绝，以及包括恐龙在内的大多数动物。最近的研究表明，多倍体物种可以具有更高的适应性和对不同环境条件的耐受性。我们建议，多倍化可能有助于生存和繁殖的几个植物谱系期间或之后的KT灭绝事件。由于基因表达的改变导致杂种优势，以及可供选择的基因和等位基因的增加，多倍体植物可能能够更好地适应6500万年前急剧变化的环境。
Most flowering plants have been shown to be ancient polyploids that have undergone one or more whole genome duplications early in their evolution. Furthermore, many different plant lineages seem to have experienced an additional, more recent genome duplication. Starting from paralogous genes lying in duplicated segments or identified in large expressed sequence tag collections, we dated these youngest duplication events through penalized likelihood phylogenetic tree inference. We show that a majority of these independent genome duplications are clustered in time and seem to coincide with the Cretaceous-Tertiary (KT) boundary. The KT extinction event is the most recent mass extinction caused by one or more catastrophic events such as a massive asteroid impact and/or increased volcanic activity. These events are believed to have generated global wildfires and dust clouds that cut off sunlight during long periods of time resulting in the extinction of approximate to 60% of plant species, as well as a majority of animals, including dinosaurs. Recent studies suggest that polyploid species can have a higher adaptability and increased tolerance to different environmental conditions. We propose that polyploidization may have contributed to the survival and propagation of several plant lineages during or following the KT extinction event. Due to advantages such as altered gene expression leading to hybrid vigor and an increased set of genes and alleles available for selection, polyploid plants might have been better able to adapt to the drastically changed environment 65 million years ago.