Gene fusion of heterophyletic gamma-globin genes in platyrrhine primates.

We performed phylogenetic analyses of HBG genes to assess its origin and interspecific variation among primates. Our analyses showed variation in HBG genes copy number ranging from one to three, some of them pseudogenes. For platyrrhines HBG genes, phylogenetic reconstructions of flanking regions recovered orthologous clades with distinct topologies for 5' and 3' flanking regions. The 5' region originated in the common ancestor of platyrrhines but the 3' region had an anthropoid origin. We hypothesize that the platyrrhine HBG genes of 5' and 3' heterophyletic origins arose from subsequent fusions of the (earlier) platyrrhine 5' portion and the (later) anthropoid 3' portion.