Two models for the nature of pleiotropy in adaptation. Left: Schematic of the environmental structure in this study. Environments can be mapped onto a multidimensional environment space characterized by chemical and physical compositions. The large green circle represents an environment where adaptive mutants evolved, and the large pink circle is a distant environment. Around each base, a set of identical environmental perturbations (arrows) is applied, generating clusters of similar environments around distinct base environments. Top right: Schematic of fitnotype map for adaptive mutants near their home base environment. By measuring fitness in each of the green environments, one can infer how many fitnotypes matter for this set of mutants in their home environment. Here, only four of the possible 8 fitnotypes matter. Bottom right: When the mutants are moved to the distant base environment, and their fitness is measured in all pink environments (base and perturbations), there are two possibilities. Either more fitnotypes become important and the space appears higher-dimensional (left, pleiotropic expansion), or the set of fitnotypes that matters remains low-dimensional, but shifts (right, pleiotropic shift).
Predicting the effect of a #mutation on #fitness is hard. @oliviamghosh.bsky.social @petrovadmitri.bsky.social &co use fitness effects of adaptive yeast mutants to show that underlying genotype-phenotype-fitness maps are low-dimensional but context-dependent @plosbiology.org 🧪 plos.io/4dLy2Ez
