title: Primate phylogeny, evolutionary rate variations, and divergence times: a contribution from the nuclear gene IRBP.
abstract: The first third (ca. 1200 bp) of exon 1 of the nuclear gene encoding the interstitial retinoid-binding protein (IRBP) has been sequenced for 12 representative primates belonging to Lemuriformes, Lorisiformes, Tarsiiformes, Platyrrhini, and Catarrhini, and combined with available data (13 other primates, 11 nonprimate placentals, and 2 marsupials). Phylogenetic analyses using maximum likelihood on nucleotides and amino acids robustly support the monophyly of primates, Strepsirrhini, Lemuriformes, Lorisiformes, Anthropoidea, Catarrhini, and Platyrrhini. It is interesting to note that 1) Tarsiidae grouped with Anthropoidea, and the support for this node depends on the molecular characters considered; 2) Cheirogaleidae grouped within Lemuriformes; and 3) Daubentonia was the sister group of all other Lemuriformes. Study of the IRBP evolutionary rate shows a high heterogeneity within placentals and also within primates. Maximum likelihood local molecular clocks were assigned to three clades displaying significantly contrasted evolutionary rates. Paenungulata were shown to evolve 2.5-3 times faster than Perissodactyla and Lemuriformes. Six independent calibration points were used to estimate splitting ages of the main primate clades, and their compatibility was evaluated. Divergence ages were obtained for the following crown groups: 13.8-14.2 MY for Lorisiformes, 26.5-27.2 MY for Lemuroidea, 39.6-40.7 MY for Lemuriformes, 45.4-46.7 MY for Strepsirrhini, and 56.7-58.4 MY for Haplorrhini. The incompatibility between some paleontological and molecular estimates may reflect the incompleteness of the placental fossil record, and/or indicate that the variable IRBP evolutionary rates are not fully accommodated by local molecular clocks.
authors.affiliation: Laboratoire de Paléontologie, Paléobiologie et Phylogénie-CC064, Institut des Sciences de l'Evolution UMR 5554/CNRS, Université Montpellier II 34095 Montpellier, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Poux
authors.forename: Emmanuel J P
authors.initials: EJ
authors.lastname: Douzery
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002138:Calibration; D005136:Eye Proteins / Q000235:genetics*; D005580:Fossils; D006801:Humans; D010802:Phylogeny; D011323:Primates / Q000235:genetics*; D012177:Retinol-Binding Proteins / Q000235:genetics*; D000099214:Retinol-Binding Proteins, Interstitial
chemical_list: D005136:Eye Proteins; D012177:Retinol-Binding Proteins; D000099214:Retinol-Binding Proteins, Interstitial