Heritabilities and genetic correlations of telomere length, tarsus length, and body condition
We found non-zero additive genetic variances (VA ) for TL (VA =0.009, HPD=[0.008, 0.010]), tarsus length (VA =0.190, HPD=[0.116, 0.315]) and body condition (VA =0.006, HPD=[0.005, 0.006]) in the natural populations (Table 2, Fig. 3). The main component contributing to variance in TL was between-year differences (VY , explaining 70% of the variance), while maternal (VM , 8%), paternal (VF , 7%), and brood variances (VB , 6%) also explained considerable proportions of the total phenotypic variance (Fig. 3). Combined, these environmental effects captured 91% of the phenotypic variance in TL. For tarsus length and condition, the main variance components were among different broods (38%) and among years (77%), respectively (Table 2, Fig. 3). The heritabilities were h2 =0.042 for TL (HPD=[0.024, 0.064]), h2 =0.076 (HPD=[0.045, 0.123]) for tarsus length, andh2 =0.028 (HPD=[0.016, 0.0.043]) for body condition. The heritability estimates were of the same magnitude in the univariate animal models (Table S2.1). There was no evidence for a genetic correlation between TL and tarsus length (rA =-0.017, HPD=[-0.120, 0.091]) or between TL and condition (rA =-0.010, HPD=[-0.079, 0.060]).
Parent-offspring regressions showed a large maternal inheritance component in TL (h2maternal =0.45±0.16, CI=[0.136, 0.758]), but no paternal inheritance (Fig. S2.2). Including parental genetic effects in a multivariate animal model confirmed slightly higher maternal (h2maternal =0.078, HPD=[0.042, 0.104]) than paternal heritability of TL (h2paternal =0.070, HPD=[0.038, 0.094], Table S2.2). We found no evidence of differences in sex-specific heritabilities of TL (Table S2.3).
In the analyses of the artificially selected populations (Leka and Vega, Table S2.4) we found comparable heritability estimates for TL (h2 =0.035, HPD=[0.008, 0.084]) and body condition (h2 =0.019, HPD=[0.004, 0.050]), and a slightly higher estimate for tarsus length (h2 =0.114, HPD=[0.045, 0.247]). Similarly, there was no evidence for genetic correlations between TL and tarsus (rA =-0.027, HPD=[-0.224, 0.181]) or between TL and body condition (rA =-0.006, HPD=[-0.130, 0.134], Table S2.4).