Per-Nucleus Crossover Covariation and Implications for Evolution
Per-Nucleus Crossover Covariation and Implications for Evolution
复制标题
每核交叉协变及其对进化的影响。
DOI：
10.1016/j.cell.2019.02.021
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发表时间：
2019-04-04
期刊：
影响因子：
64.5
通讯作者：
Zhang, Liangran
中科院分区：
文献类型：
--
作者：
Wang, Shunxin;Veller, Carl;Zhang, Liangran
交换几乎是有性生殖的普遍特征。在这里，对每个染色体和每个细胞核的交叉数的分析揭示了减数分裂的一个基本的、进化上保守的特征：在单个细胞核内，交叉频率在不同的染色体之间是协变的。这种效应是由染色体轴长的核协变引起的。交叉可以促进进化适应。然而，创造有利的新等位基因组合的好处必须超过破坏现有有利组合的成本。共变异伴随着增加配子的频率，特别是高，或特别低，交换的数量，因此可能伴随着增加交换的好处，同时降低其成本。一个四位点的群体遗传模型表明，这样的效果可以适用于环境波动的情况下：超交叉配子是有利的，当环境变化，而次交叉配子是有利的，在环境停滞期。这些发现揭示了基本减数分裂程序的一个新特征，并提出了可能的适应性优势。
Crossing over is a nearly universal feature of sexual reproduction. Here, analysis of crossover numbers on a per-chromosome and per-nucleus basis reveals a fundamental, evolutionarily conserved feature of meiosis: within individual nuclei, crossover frequencies covary across different chromosomes. This effect results from per-nucleus covariation of chromosome axis lengths. Crossovers can promote evolutionary adaptation. However, the benefit of creating favorable new allelic combinations must outweigh the cost of disrupting existing favorable combinations. Covariation concomitantly increases the frequencies of gametes with especially high, or especially low, numbers of crossovers, and thus might concomitantly enhance the benefits of crossing over while reducing its costs. A four-locus population genetic model suggests that such an effect can pertain in situations where the environment fluctuates: hyper-crossover gametes are advantageous when the environment changes while hypo-crossover gametes are advantageous in periods of environmental stasis. These findings reveal a new feature of the basic meiotic program and suggest a possible adaptive advantage.