论文标题
多倍体的进化创新
Evolutionary Innovation by Polyploidy
论文作者
论文摘要
进化创新的首选条件是一个基本问题,但鲜为人知,部分原因是该问题涉及罕见事件。我们专注于多倍体在新特征进化中的潜在作用。关于多倍体对进化的影响,有两个假设:多倍体减少了单个突变的影响并减慢了进化。相反,多倍体引入的基因冗余将促进新功能化和加速进化。多倍体会加快或减慢进化吗?在这项研究中,我们提出了一个简单的多倍体细胞模型,并表明多倍体的进化速率与中性选择或逐渐进化过程中的单倍体相似或慢。但是,在适应性景观中,细胞应跳过致命山谷以提高其适应性,可以大大增加多倍体进化的可能性,并且鉴定出最佳的染色体数量。从理论上讲,我们从大偏差理论中讨论了这种最佳染色体数的存在。此外,我们提出,实现进化创新的优化可以确定多倍体细菌中染色体数的范围。
The preferred conditions for evolutionary innovation is a fundamental question, but little is known, in part because the question involves rare events. We focused on the potential role of polyploidy in the evolution of novel traits. There are two hypotheses regarding the effects of polyploidy on evolution: Polyploidy reduces the effect of a single mutation and slows evolution. In contrast, the gene redundancy introduced by polyploidy will promote neofunctionalization and accelerate evolution. Does polyploidy speed up or slow down evolution? In this study, we proposed a simple model of polyploid cells and showed that the evolutionary rate of polyploids is similar to or much slower than that of haploids under neutral selection or during gradual evolution. However, on a fitness landscape where cells should jump over a lethal valley to increase their fitness, the probability of evolution in polyploidy could be drastically increased, and the optimal number of chromosomes was identified. We theoretically discussed the existence of this optimal chromosome number from the large deviation theory. Furthermore, we proposed that the optimization for achieving evolutionary innovation could determine the range of chromosome numbers in polyploid bacteria.