基因组冗余如何促进进化创新
How genome redundancy can promote evolutionary innovation
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中文总结 AI 辅助
研究多倍体在不同选择压力下与遗传模式、基因型-表型映射的相互作用，通过最小进化模型发现多倍体在环境突变时有利，随机遗传与非线性映射效果最佳，结构化遗传有最优值，为理解多倍体受自然选择青睐提供统一框架。
中文摘要 AI 辅助
多倍体被定义为存在两套以上完整的同源染色体。尽管它在生命之树中广泛存在，但其作为进化创新或死胡同的作用仍存在争议。在此，我们研究在不同选择压力下，倍性程度如何与两个关键生物学因素相互作用：遗传模式和基因型-表型映射。通过一个最小进化模型，我们发现多倍体在环境突然变化时特别有利，证实多倍体化常与生态剧变相关。我们观察到随机遗传与非线性（基于最大值）基因型-表型映射在所有环境中都能使表型利用和景观探索最大化。相比之下，具有加性表型映射的结构化遗传系统表现较差，但在低到中等倍性水平显示出明显的最优值，反映了在自然植物和细菌种群中观察到的分布。当个体可以自由携带不同染色体数时，选择会驱使种群趋向反映利用、探索和收敛速度之间相互作用的值，而非任何单一进化目标。这三个因素的相对权重取决于适应度景观，为理解何时以及为何多倍体受自然选择青睐提供了一个统一框架。
英文摘要
Polyploidy is defined as the existence of more than two complete sets of homologous chromosomes. Despite it being a widespread phenomenon across the tree of life, its role as either an evolutionary innovation or a dead end is still debated. Here, we investigate how under varying selective pressures the degree of ploidy interacts with two key biological factors: the mode of inheritance and the genotype-phenotype mapping. Through a minimal evolutionary model we find that polyploidy is especially advantageous during abrupt environmental changes, confirming that polyploidization is often associated with ecological upheavals. We observe that stochastic inheritance combined with a nonlinear (maximum-based) genotype-phenotype mapping maximizes both phenotypic exploitation and landscape exploration across all environments. By contrast, structured inheritance with an additive phenotype mapping systematically underperforms, yet displays a pronounced optimum at low-to-intermediate ploidy level that mirrors the distribution observed in natural plant and bacterial populations. When individuals are free to carry different chromosome numbers, selection drives the population toward values that reflect an interplay between exploitation, exploration, and convergence speed rather than any single evolutionary objective. The relative weight of these three factors depends on the fitness landscape, providing a unifying framework for understanding when and why polyploidy is favored by natural selection.
