Correlation between conservation of gene location and gene expression similarity. (A) Boxplots of expression divergences among nonessential orthologs with highly conserved and divergent genomic neighborhoods (***P < 10−5). (B) Same as A for essential genes. Interestingly, the trend is opposite for essential genes (*P < 0.05). (C) A gene with an overall conserved gene order; (D) a gene whose orthologs are situated in divergent neighborhoods. The horizontal lines indicate the C. elegans and C. briggsae chromosomes, and the vertical gray bars indicate neighboring genes. Black lines indicate a one-to-one orthologous relationship. The plots to the right show the standardized temporal expression profile for the one-to-one orthologs.
