Phenotypic correlates of variation at the Clock gene in a wild blue tit population: evidence for a role in seasonal timing of reproduction
The timing of reproduction in birds varies considerably within populations and is often under strong natural selection. Individual timing within years is dependent on a range of environmental factors in addition to having an additive genetic basis. In vertebrates, an increasing amount is known about the molecular basis for variation in biological timing. The Clock gene includes a variable poly-glu