The phylogenetic relationship of duplicate protein pairs and their highest matching ortholog sequences. Maximum likelihood trees representing four of these relationships are shown above for hisD
, sdhB and frdB, sac1 and a hypothetical protein, and traI and a hypothetical protein. Each of these unrooted trees displayed a bootstrap value of 100. The offshoots represent branches and their lengths are given (trees are not to scale). The relationships depict two types of topology - Type A or Type B.