Data from: Ontogeny tends to recapitulate phylogeny in digital organisms

Biologists have long debated whether ontogeny recapitulates phylogeny and, if so, why. Two plausible explanations are that (i) changes to early developmental stages are selected against because they tend to disrupt later development and (ii) simpler structures often precede more complex ones in both ontogeny and phylogeny if the former serve as building blocks for the latter. It is difficult to test these hypotheses experimentally in natural systems, so we used a computational system that exhibits evolutionary dynamics. We observed that ontogeny does indeed recapitulate phylogeny; traits that arose earlier in a lineage’s history also tended to be expressed earlier in the development of individuals. The relative complexity of traits contributed substantially to this correlation, but a significant tendency toward recapitulation remained even after accounting for trait complexity. This additional effect provides evidence that selection against developmental disruption also contributed to the conservation of early stages in development.

长期以来，生物学家一直围绕个体发育（ontogeny）是否重演系统发育（phylogeny），以及若该现象成立其背后的机制展开了广泛争论。目前存在两种较为合理的假说：其一，早期发育阶段的变异往往会干扰后续发育进程，因此这类变异会被自然选择所淘汰；其二，若某类结构可作为更复杂结构的构建基础，则无论在个体发育还是系统发育进程中，结构简单的类型往往会先于结构复杂的类型出现。由于在自然系统中难以通过实验手段验证上述假说，本研究采用了一套具备进化动力学特征的计算系统。研究结果显示，个体发育确实会重演系统发育：在物种谱系的历史中较早出现的性状，往往也会在个体发育过程中更早得以表达。性状的相对复杂度对这一相关性具有显著贡献，但即便在控制性状复杂度的影响后，重演现象仍存在显著的统计学趋势。这一额外效应表明，针对发育干扰的选择压力同样对发育早期阶段的演化保守性起到了推动作用。