Low variability and absence of phenotypic correlates of Clock gene variation in a great tit Parus major population
Studies of a range of taxa, including birds, have revealed latitudinal clines in allele length at the conserved Clock locus, a gene with known influences on behaviour and physiology. Such clines might reflect adaptation to seasonal variation, a suggestion supported by a recent within-population analysis of blue tits Cyanistes caeruleus, which found associations between Clock genotype and timing of