Figure 1.
Frequency distributions of percent difference in total coding sequence length (exons only) between human and mouse orthologs (light gray) and between human and chimpanzee orthologs (black) for 7645 protein-coding genes. Forty-nine percent of the genes exhibit some length difference between human and mouse; human and chimpanzee orthologs exhibit length difference in only 17 of these 7645 genes. Data from Clark et al. (2003).
