Characterization of linne, a new autosomal eclosion rhythm mutant in Drosophila subobscura

A new putative gene, named linne, affecting circadian eclosion rhythm was found in a Norwegian strain of Drosophila subobscura. The phenotype of linne may be novel among Drosophila clock mutants. Eclosion is practically arrhythmic in light-dark cycles, but diel temperature cycles of 4 degrees C amplitude effectively entrain eclosion in continuous light and in continuous darkness. After that, the rhythm continues in constant temperature and darkness, but unlike other strains, it continues in constant temperature and light as well. Thus in the linne strain the coupling between light signals and pacemaker is disrupted, not the pacemaker itself. Genetic effects of linne were tested in crosses with a wild strain. Arrhythmicity was recessive and autosomal and showed monogenic inheritance, suggesting that arrhythmicity in linne is based on mutation on a single locus.