Evolutionary conservation of co-expression improves disease candidate gene prioritization performance over human-only co-expression. The disease gene rank histogram shows the relative proportions of disease genes scoring in different rank bins based on co-expression with known disease genes causing the same disease. Disease gene rank indicates its degree of co-expression with known disease genes, relative to those of the other locus candidate genes. Evolutionary conservation results in a much higher proportion of disease genes ranking in the top 10% of the locus candidate genes and fewer in the mid-regions of the lists. A) Disease gene rank histogram. B) Cumulative proportion of disease genes detected as the co-expression rank threshold is decreased from 1 to 0.