Estimating pairwise correlation coefficients across genes reveals new networks of correlated expression evolution.

A-B Comparison of the distribution of Pearson’s correlation coefficients based on ovary-biased expression evolution between genes. Box plots indicate mean, upper and lower quartiles, and 1.5x interquartile ranges. Asterisks indicate a significant t-test comparison. A, Genes with no or unknown protein-protein interactions compared to those with reported interactions in FlyBase [52] (maximum p-value = Fig 4D). Yellow = strong positive correlation, purple = strong negative correlation. D, The network of strong correlation partners (absolute correlation > 0.825) with the yolk-protein genes, colored by the direction of correlation. Stronger correlations are shown by brighter colors, and thicker, shorter lines. Nodes are annotated with the gene symbols from the D. melanogaster sequences from that homology group. E, The correlation between known protein-protein interaction partners [52] with the yolk-protein genes.