How development affects evolution

Abstract

How development affects evolution. A mathematical framework that explicitly integrates development into evolution has recently been derived. Here we use this framework to analyse how development affects evolution. We show that, whilst selection pushes genetic and phenotypic evolution uphill on the fitness landscape, development determines the admissible evolutionary pathway, such that evolutionary outcomes occur at path peaks, which need not be peaks of the fitness landscape. Development can generate path peaks, triggering adaptive radiations, even on constant, single-peak landscapes. Phenotypic plasticity, niche construction, extra-genetic inheritance, and developmental bias variously alter the evolutionary path and hence the outcome. Selective development, whereby phenotype construction may point in the adaptive direction, may induce evolution either towards or away landscape peaks depending on the developmental constraints. Additionally, developmental propagation of phenotypic effects over age allows for the evolution of negative senescence. These results help explain empirical observations including punctuated equilibria, the paradox of stasis, the rarity of stabilizing selection, and negative senescence, and show that development has a major role in evolution.

Evo-devo dynamics of hominin brain size

“…S32). That socio-genetic covariation determines evolutionary outcomes despite no internal fitness landscape peaks is possible because there is socio-genetic covariation only along the path where the developmental constraint is met (so L z is always singular 29 ) and consequently evolutionary outcomes occur at path peaks rather than landscape peaks 31 (Box 1 Fig. b).…”

“…3b), which can be compensated by high socio-genetic covariation with developmentally late reproductive tissue. Such high covariation can arise because of developmental propagation of phenotypic effects of mutations 31 . The role of ecology and culture in driving brain expansion in the brain model is thus to generate positive socio-genetic covariation between brain size and developmentally late reproductive tissue.…”

“…Eq. (M5) and the formulas for L z entail that evolution proceeds as the climbing of the fitness landscape in geno-phenotype space, where the developmental constraint (M1) provides the admissible evolutionary path, such that evolutionary outcomes occur at path peaks rather than landscape peaks if there are no absolute mutational constraints 31 .…”

“…b;from ref. 31 ). Thus, while selection pushes evolution uphill on the fitness landscape of the genotype and phenotype (or geno-phenotype), developmental constraints drive evolution to an outcome at a path peak.…”

Developing the genotype‐to‐phenotype relationship in evolutionary theory: A primer of developmental features

“…This shifts the types of evolutionary questions we can answer, from thinking about the sorting of existing genetic variation, to the origin of novel traits, the patterns of cryptic genetic variation, and divergence across lineages. Expanding basic evolutionary models with developmental features shows how development shapes possible evolutionary paths (González‐Forero, 2022).…”