Santa Fe Institute, Santa Fe, NM, 87501, USA.
Ecology, Evolution and Behavior, University of Minnesota, Minneapolis, MN, 55108, USA.
Sci Rep. 2018 Jan 18;8(1):1120. doi: 10.1038/s41598-017-18687-y.
Programmed cell death (PCD) occurs in both unicellular and multicellular organisms. While PCD plays a key role in the development and maintenance of multicellular organisms, explaining why single-celled organisms would evolve to actively commit suicide has been far more challenging. Here, we explore the potential for PCD to act as an accessory to microbial bet-hedging strategies that utilize stochastic phenotype switching. We consider organisms that face unpredictable and recurring disasters, in which fitness depends on effective phenotypic diversification. We show that when reproductive opportunities are limited by carrying capacity, PCD drives population turnover, providing increased opportunities for phenotypic diversification through stochastic phenotype switching. The main cost of PCD, providing resources for growth to a PCD(-) competitor, is ameliorated by genetic assortment in spatially structured populations. Using agent -based simulations, we explore how basic demographic factors, namely bottlenecks and local dispersal, can generate sufficient spatial structure to favor the evolution of high PCD rates.
程序性细胞死亡（PCD）发生在单细胞生物和多细胞生物中。虽然 PCD 在多细胞生物的发育和维持中起着关键作用，但解释为什么单细胞生物会进化为主动自杀一直更具挑战性。在这里，我们探讨了 PCD 作为利用随机表型转换的微生物贝叶斯策略的辅助手段的可能性。我们考虑了那些面临不可预测和反复发生的灾难的生物体，在这些灾难中，适应性取决于有效的表型多样化。我们表明，当生殖机会受到承载能力的限制时，PCD 会推动种群更替，通过随机表型转换提供更多的表型多样化机会。PCD 的主要成本是为 PCD(-)竞争提供资源，这在空间结构种群中的遗传组合中得到缓解。我们使用基于主体的模拟来探讨基本的人口统计因素，即瓶颈和局部扩散，如何产生足够的空间结构，有利于高 PCD 率的进化。
