Maximum-likelihood reconstruction of the zinc finger phylogeny, colored by genus. Each finger is represented with a colored bar, and branches with strong approximate likelihood ratio test (aLRT) values (greater than 0.8) are marked with circles. The most 5′ fingers from all genera form a clear clade with an aLRT value of 1. The most 3′ “stop” fingers are also closely related (aLRT value 0.86) in several distantly related genera. In contrast, intra-species similarity can be seen throughout the rest of the tree, where fingers from the same or closely related genera form clusters, consistent with a concerted evolution mechanism. This is most clearly exhibited in the New World Monkeys, where nearly all internal fingers are very closely related to one another, especially in the Callithrix jacchus (brown bars).