Am Nat. 2022 Dec;200(6):755-772. doi: 10.1086/721766. Epub 2022 Oct 7.
AbstractThe adaptive potential of nonheritable somatic mutations has received limited attention in traditional evolutionary theory because heritability is a fundamental pillar of Darwinian evolution. We hypothesized that the ability of a germline genotype to express a novel phenotype via nonheritable somatic mutations can be selectively advantageous and that this advantage will channel evolving populations toward germline genotypes that constitutively express the phenotype. We tested this hypothesis by simulating evolving populations of developing organisms with an impermeable germline-soma separation navigating a minimal fitness landscape. The simulations revealed the conditions under which nonheritable somatic mutations promote adaptation. Specifically, this can occur when the somatic mutation supply is high, when few cells with the advantageous somatic mutation are required to increase organismal fitness, and when the somatic mutation also confers a selective advantage at the cellular level. We therefore provide proof of principle that nonheritable somatic mutations can promote adaptive evolution via a process we call "somatic genotypic exploration." We discuss the biological plausibility of this phenomenon as well as its evolutionary implications.
摘要
非遗传性体细胞突变的适应潜力在传统进化理论中受到的关注有限，因为遗传性是达尔文进化的一个基本支柱。我们假设，通过非遗传性体细胞突变表达新表型的生殖系基因型可以具有选择优势，并且这种优势将使进化种群朝着持续表达该表型的生殖系基因型方向发展。我们通过模拟具有不可渗透的生殖系-体分离的发育生物种群在最小适应度景观中导航来检验这个假设。模拟结果揭示了非遗传性体细胞突变促进适应的条件。具体来说，当体细胞突变供应高、少数具有有利体细胞突变的细胞就可以提高生物体适应性，并且当体细胞突变也在细胞水平赋予选择优势时，这种情况就会发生。因此，我们提供了一个原理性证明，即非遗传性体细胞突变可以通过我们称之为“体细胞基因探索”的过程来促进适应性进化。我们讨论了这种现象的生物学可能性及其进化意义。
