This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (11) Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Nadkarni, N. A. Articles by Thomas, M. G. Search for Related Content PubMed PubMed Citation Articles by Nadkarni, N. A. Articles by Thomas, M. G. Social Bookmarking                         What's this?

Evolution of a Length Polymorphism in the Human PER3 Gene, a Component of the Circadian System

Department of Biology University College London, United Kingdom; Molecular Imaging Group, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, United Kingdom

Michael E. Weale

Department of Medicine, University College London, United Kingdom

Malcolm von Schantz

Centre for Chronobiology, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, United Kingdom

Mark G. Thomas

Department of Biology; Department of Biology, University College London, Gower Street, London, WC1E 6BT, UK;m.thomas{at}ucl.ac.uk

Period homologue 3 (PER3) is a component of the mammalian circa-dian system, although its precise role is unknown. A biallelic variable number tandem repeat (VNTR) polymorphism exists in human PER3, consisting of 4 or 5 repeats of a 54-bp sequence in a region encoding a putative phosphorylation domain. This polymorphism has previously been reported to associate with diurnal preference ("morningness" and "eveningness") and delayed sleep-phase syndrome. We have investigated the global allele frequencies of this variant in ethnically distinct indigenous populations. All populations were polymorphic, with the shorter (4-repeat) allele ranging in frequency from 0.19 (Papua New Guinea) to 0.89 (Mongolia). To investigate if allele frequency has been influenced by natural selection, the authors 1) tested for a correlation with latitude and mean annual insolation (incident sunlight energy), using classical markers to correct for historical population differentiation; and they 2) compared allele-frequency difference between European American, African American, and East Asian populations, as measured using F_ST, to an empirical null distribution of F_STvalues based on a genome-wide dataset of single nucleotide polymorphisms (SNPs) of presumed neutral loci that were previously typed by The SNP Consortium. The variation in allele frequencies between indigenous populations did not show a pattern that would indicate selective pressure on PER3resulting from day-length variation or mean annual insolation, and the allele-frequency difference between European Americans, African Americans, and East Asians was not an outlier when compared to the distribution for presumed neutral SNPs. We therefore find no evidence for differential or balancing selection in the contemporary pattern of global PER3allele frequencies.

Key Words: PER3 • circadian rhythms • polymorphism • natural selection • day length

Journal of Biological Rhythms, Vol. 20, No. 6, 490-499 (2005)
DOI: 10.1177/0748730405281332


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				C. M. Ciarleglio, K. K. Ryckman, S. V. Servick, A. Hida, S. Robbins, N. Wells, J. Hicks, S. A. Larson, J. P. Wiedermann, K. Carver, et al. Genetic Differences in Human Circadian Clock Genes among Worldwide Populations J Biol Rhythms, August 1, 2008; 23(4): 330 - 340. [Abstract] [PDF]