Figure 2. Proportion of Genes Evolving Adaptively in Each Expression Category and for Each Feature.

Genes with increased expression levels have associated recurrent adaptive evolution of 3′ UTR and 3′ flanking regions as well as evidence for recent adaptive evolution of protein coding regions. For resampling tests, *p < 0.05 and **p < 0.01. Descriptions of tests for recurrent and recent adaptive evolution can be found in the Materials and Methods section.