Data from: Macroevolution along developmental lines of least resistance

A reigning paradigm in biology is that short-term evolution can be
predicted from measures of genetic variation within populations, but that
the accuracy of such predictions should decay with time. Here, we show
that intrinsic developmental variability and standing genetic variation in
wing shape of the two flies, Drosophila melanogaster and Sepsis punctum,
are tightly aligned and predict deep divergence in the dipteran phylogeny,
spanning >900 taxa and 185 My of evolution. This finding is hard to
reconcile with constraint hypotheses invoking a lack of genetic variation
as the reason for slow-evolving wing traits unless most of the observed
variability is associated with deleterious side effects and effectively
unusable for evolution. However, phenotyping of 71 genetic lines of S.
punctum revealed no association between variation in wing shape and
fitness correlates unrelated to flight, lending no credence to this
hypothesis. We also find no evidence for genetic constraints on the pace
of wing shape evolution along individual branches of the phylogeny.
Instead, correlational selection related to allometric scaling,
simultaneously shaping both developmental bias and deep divergence in fly
wings, emerges as the most plausible explanation for the observed
patterns. This suggests that past forces of selection have shaped the
developmental architecture of the dipteran wing such that its long-term
evolution can be predicted from its intrinsic variability. These findings
challenge our understanding of the fundamental processes governing the
emergence of phenotypic variation and its evolution.