MOLECULAR PHYLOGENY OF THE NEW-WORLD MONKEYS (PLATYRRHINI, PRIMATES) BASED ON 2 UNLINKED NUCLEAR GENES - IRBP INTRON-1 AND EPSILON-GLOBIN SEQUENCES

Nuclear sequences of the 1.8 kilobase (kb) long intron 1 of the inters titial retinol-binding protein gene (IRBP), previously determined for 11 of the 16 extant genera of New World monkeys (superfamily Ceboidea, infraorder Platyrrhini), have now been determined for the remaining 5 genera. The maximum parsimony trees found, first with IRBP sequences alone and then with tandemly combined IRBP and E-globin gene sequences from the same species, supported a provisional cladistic classificati on with the following clusters. Subtribes Callitrichina (Callithrix, C ebuella), Callimiconina (Callimico), Leontopithecina (Leontopithecus) and Saguina (Saguinus) constitute subfamily Callitrichinae, and subfam ilies Callitrichinae, Aotinae (Aotus), and Cebinae (Cebus, Saimiri) co nstitute family Cebidae. Subtribes Chiropotina(Chiropotes, Cacajao) an d Pitheciina (Pithecia) constitute tribe Pitheciini; and tribes Pithec iini and Callicebini (Callicebus) constitute subfamily Pitheciinae. Su btribes Brachytelina (Brachyteles, Lagothrix) and Atelina (Ateles) con stitute tribe Atelini, and tribes Atelini and Alouattini (Alouatta) co nstitute subfamily Atelinae. The parsimony results were equivocal as t o whether Pitheciinae should be grouped with Atelinae in family Atelid ae or have its own family Pitheciidae, The cladistic groupings of exta nt ceboids were also examined by different stochastic evolutionary mod els that employed the same stochastic process of nucleotide substituti ons but alternative putative phylogenetic trees on which the nucleotid e substitutions occurred. Each model, i.e., each different tree, predi cted a different multinomial distribution of nucleotide character patt erns for the contemporary sequences. The predicted distributions that were closest to the actual observed distributions identified the best fitting trees. The cladistic relationships depicted in these best fitt ing trees agreed in almost all cases with those depicted in the maximu m parsimony trees. (C) 1996 Wiley-Liss, Inc.