title: Evolutionary history of the PER3 variable number of tandem repeats (VNTR): idiosyncratic aspect of primate molecular circadian clock.
abstract: The PER3 gene is one of the clock genes, which function in the core mammalian molecular circadian system. A variable number of tandem repeats (VNTR) locus in the 18th exon of this gene has been strongly associated to circadian rhythm phenotypes and sleep organization in humans, but it has not been identified in other mammals except primates. To better understand the evolution and the placement of the PER3 VNTR in a phylogenetical context, the present study enlarges the investigation about the presence and the structure of this variable region in a large sample of primate species and other mammals. The analysis of the results has revealed that the PER3 VNTR occurs exclusively in simiiforme primates and that the number of copies of the primitive unit ranges from 2 to 11 across different primate species. Two transposable elements surrounding the 18th exon of PER3 were found in primates with published genome sequences, including the tarsiiforme Tarsius syrichta, which lacks the VNTR. These results suggest that this VNTR may have evolved in a common ancestor of the simiiforme branch and that the evolutionary copy number differentiation of this VNTR may be associated with primate simiiformes sleep and circadian phenotype patterns.
authors.affiliation: Department of Psychobiology, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Flávia Cal
authors.initials: FC
authors.lastname: Sabino
authors.affiliation: Department of Genetics and Evolutionary Biology, University of São Paulo, São Paulo, Brazil.
authors.forename: Amanda Oliveira
authors.initials: AO
authors.lastname: Ribeiro
authors.affiliation: Department of Psychobiology, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Sérgio
authors.initials: S
authors.lastname: Tufik
authors.affiliation: Evandro Chagas Institute/Primate National Center (IEC-CENP) - Health Surveillance Secretariat, Brazilian Ministry of Health, Ananindeua, Pará, Brazil.
authors.forename: Laila Brito
authors.initials: LB
authors.lastname: Torres
authors.affiliation: Division of Anatomy, Department of Basic Sciences, Araçatuba Dental School, São Paulo State University, Araçatuba, Brazil.
authors.forename: José Américo
authors.initials: JA
authors.lastname: Oliveira
authors.affiliation: Department of Physiology, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Luiz Eugênio Araújo Moraes
authors.initials: LE
authors.lastname: Mello
authors.affiliation: Laboratory of Neurochemical Studies, Federal University of Rio Grande do Norte, Natal, Brazil.
authors.forename: Jeferson Souza
authors.initials: JS
authors.lastname: Cavalcante
authors.affiliation: School of Arts, Science and Humanities, University of São Paulo, São Paulo, Brazil.
authors.forename: Mario
authors.initials: M
authors.lastname: Pedrazzoli
mesh_terms: D000818:Animals; D057906:Circadian Clocks / Q000235:genetics*; D003198:Computer Simulation; D056915:DNA Copy Number Variations; D019143:Evolution, Molecular; D018598:Minisatellite Repeats; D056950:Period Circadian Proteins / Q000737:chemistry*; D011323:Primates / Q000235:genetics*
chemical_list: D056950:Period Circadian Proteins