Figure 5.6 The globin gene superfamily. Illustration of the evolution and genomic organization of all mouse globin-like genes. The members of each of the two individual clusters are more closely related to each other than any are to other members of the superfamily. This suggests that each cluster was seeded by a single transposed gene that duplicated later by unequal crossing over into all other members of the local family. Dark boxes represent functional genes and open boxes represent pseudogenes.