Avian Clock gene polymorphism: Evidence for a latitudinal cline in allele frequencies

A. Johnsen*, A. E. Fidler, S. Kuhn, K. L. Carter, A. Hoffmann, I. R. Barr, C. Biard, A. Charmantier, M. Eens, P. Korsten, H. Siitari, J. Tomiuk, B. Kempenaers

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

116 Citations (SciVal)
31 Downloads (Pure)


In comparison with most animal behaviours, circadian rhythms have a well-characterized molecular genetic basis. Detailed studies of circadian clock genes in 'model' organisms provide a foundation for interpreting the functional and evolutionary significance of polymorphic circadian clock genes found within free-living animal populations. Here, we describe allelic variation in a region of the avian Clock orthologue which encodes a functionally significant polyglutamine repeat (ClkpolyQcds), within free-living populations of two passerine birds, the migratory bluethroat (Luscinia svecica) and the predominantly nonmigratory blue tit (Cyanistes caeruleus). Multiple ClkpolyQcds alleles were found within populations of both species (bluethroat: 12 populations, 7 alleles; blue tit: 14 populations, 9 alleles). Some populations of both species were differentiated at the ClkpolyQcds locus as measured by FST and RST values. Among the blue tit, but not bluethroat populations, we found evidence of latitudinal clines in (i) mean ClkpolyQcds repeat length, and (ii) the proportions of three ClkpolyQcds genotype groupings. Parallel analyses of microsatellite allele frequencies, which are considered to reflect selectively neutral processes, indicate that interpopulation allele frequency variation at the ClkpolyQcds and microsatellite loci does not reflect the same underlying demographic processes. The possibility that the observed interpopulation ClkpolyQcds allele frequency variation is, at least in part, maintained by selection for microevolutionary adaptation to photoperiodic parameters correlated with latitude warrants further study.

Original languageEnglish
Pages (from-to)4867-4880
Number of pages14
JournalMolecular Ecology
Issue number22
Publication statusPublished - 10 Oct 2007
Externally publishedYes


  • Circadian
  • Clock
  • Cyanistes
  • Luscinia
  • Polyglutamine
  • Polymorphism


Dive into the research topics of 'Avian Clock gene polymorphism: Evidence for a latitudinal cline in allele frequencies'. Together they form a unique fingerprint.

Cite this