biostudies-literatureBrisevac DEuropean Research CouncilMax-Planck-Gesellschafte1010763https://www.ebi.ac.uk/biostudies/studies/S-EPMC10286985biostudies-literatureUnknown19(6)Genetic variants underlying traits that become either non-adaptive or selectively neutral are expected to have altered evolutionary trajectories. Uncovering genetic signatures associated with phenotypic loss presents the opportunity to discover the molecular basis for the phenotype in populations where it persists. Here we study circalunar clocks in populations of the marine midge Clunio marinus. The circalunar clock synchronizes development to the lunar phase, and it is set by moonlight and tidal cycles of mechanical agitation. Two out of ten studied populations have lost their sensitivity to mechanical agitation while preserving sensitivity to moonlight. Intriguingly, the F1 offspring of the two insensitive populations regained the sensitivity to mechanical entrainment, implying a genetiPLoS geneticsGenetic analysis of a phenotypic loss in the mechanosensory entrainment of a circalunar clock.PMC10286985802923Prakash CBrisevac DKaiser TSfalseGenetic analysis of a phenotypic loss in the mechanosensory entrainment of a circalunar clock.Genetic variants underlying traits that become either non-adaptive or selectively neutral are expected to have altered evolutionary trajectories. Uncovering genetic signatures associated with phenotypic loss presents the opportunity to discover the molecular basis for the phenotype in populations where it persists. Here we study circalunar clocks in populations of the marine midge Clunio marinus. The circalunar clock synchronizes development to the lunar phase, and it is set by moonlight and tidal cycles of mechanical agitation. Two out of ten studied populations have lost their sensitivity to mechanical agitation while preserving sensitivity to moonlight. Intriguingly, the F1 offspring of the two insensitive populations regained the sensitivity to mechanical entrainment, implying a geneti2023-01-01T00:00:00Z2023 Jun2026-04-29T02:35:31.124Z2025-02-19T01:20:24.55ZS-EPMC102869853734779110.1371/journal.pgen.1010763