Fig. 1.

Scatter plot of predicted genetic variance in gene expression based on a strictly neutral model versus observed genetic variance. The solid line represents the neutral prediction. Predicted and observed genetic variances are plotted for genes in Caenorhabditis elegans (blue triangles, 930 genes), Drosophila melanogaster (green boxes, 563 genes), and Saccharomyces cerevisiae (orange diamonds, 3,405 genes). Points plotted are the medians of the posterior distributions for each gene. Caenorhabditis elegans genes with confidence intervals that overlap neutrality are shaded in gray (seven genes for which P > 0.05).