Period estimates of CCR2::LUC expression in (A) three independent HIFs (57, 92, and 343) harboring either the Bay-0 or the Sha allele at QTL confidence interval (B) parental accessions and NIL-S with introgression of Sha at QTL confidence interval in otherwise homogeneous Bay-0 background, under LL and in DD. (C) Schematic diagram showing the fine mapping strategy of chr2 locus. Black and gray bars represent Bay-0 and Sha genotypes, respectively. The names below the bars represent the molecular markers used for genotyping, and the numbers above correspond to their physical position on the genome. The crosses represent the position of the recombination event. Two recombinants, 89-S and 539-B, were found to have a recombination event surrounding a 40-Kb region, where nine annotated genes are located, as indicated below the solid bar. (D) Free-running profile of CCR2::LUC expression in recombinants 89-S, 539-B and Bay-0 under continuous red and blue light (LL). (E) Period estimates of rhythm shown in (D). All error bars indicate SEM, where n ≥ 24. Mean values that are significantly different from Bay-0 wild type are indicated by *, **, or *** for p-values (ANOVA) <0.05, 0.01, or 0.001, respectively.