Fold enrichments of HI genes in different evolutionary ages. The horizontal axis represents evolutionary age and the vertical axis represents the fold enrichment. Values are sorted by evolutionary branch. Branch 0 indicates the oldest genes and branches 8 ~ 12 indicate primate-specific young genes. Significantly enriched branches are labelled with asterisks (*: P < 0.05; **: P < 0.01; ***: P < 0.001).
Zhou et al. BMC Genomics 2013 14:67 doi:10.1186/1471-2164-14-67