Figure 3.

Allele and chronotype frequency and chronotype association of the PER3 SNP and VNTR in elite swimmers. A) The PER3 G allele is more frequent in ET (n = 7) than in MT and NT (n = 19) (OR = 6.800, phi = 1.45, p = 0.148). B) Genotypes with a G present have a significantly lower average MEQ score (M = 41.4 ± 4.55) than CC genotypes (M = 47.9 ± 1.11) (t = 13.7, df = 24, p = 0.046). C) The PER3 5 repeat allele is most prevalent in intermediates but does not have a significant association with a specific chronotype (OR = 0.208, phi = 0.28, p = 0.208). D) Participants with a heterozygous VNTR genotype (PER3^4/5) do not have higher average MEQ scores (M = 47.6 ± 3.47) than participants with the homozygous (PER3^4/4) genotype (M = 46 ± 8.10; t = 0.545, df = 23, p = 0.591). E) The PER3 ‘evening’ haplotype (a G-allele and PER3^4/4) is more frequent in ET than in MT and NT (OR = 8.000, phi = 1.63, p = 0.103). F) The average MEQ score is significantly lower in participants with the PER3 eveningness haplotype—individuals homozygous for the 4-repeat VNTR (PER3^4/4 genotype) and possessing a G allele—than the average of all the other genotypes (M_eve = 40 ± 5.583; M_other = 47.86 ± 1.082; t = 5.64, df = 23, p = 0.026).