Abstract
Phenotypes typically display integration, i.e. correlations between traits. For quantitative traits—like many behaviors, physiological processes, and life-history traits— patterns of integration are often assumed to have been shaped by the combination of linear, non-linear, and correlated selection, with trait correlations representative of optimal combinations and reflective of the adaptive landscapes that have shaped a population. Unfortunately, this assumption has rarely been critically tested, in part due to a lack of clear alternatives. Here we show that trait integration across 6 phyla and 60 species (including both Plantae and Animalia) is consistent with evolution across high dimensional “holey landscapes” rather than classical models of selection. This suggests that the leading conceptualizations and modeling of the evolution of trait integration fail to capture how phenotypes are shaped and that traits are integrated in a manner contrary to predictions of dominant evolutionary theory.
One-Sentence Summary Patterns of correlations among traits are inconsistent with dominant models of evolution and suggest, instead, that quantitative traits have predominantly evolved via drift of populations across high dimensional holey landscapes.
Competing Interest Statement
The authors have declared no competing interest.