Fig. 4.
Effect of protein-sequence evolution on patterns of gene-expression divergence. Nonlinear regression was used to estimate the drift parameter σ and equilibrium variance σ2/2λ in sliding windows across gene rank ordered according to their rate of protein-sequence evolution. Each window consists of 1,125 genes, or 25% of the total set of genes in which reliable alignments could be made. Mean estimates are shown as solid lines and 95% CIs shown as gray boundaries. Fast-evolving genes show similar rates of drift, but significantly greater levels of equilibrium variance, compared to slow-evolving genes.