Linear mixed effects model to test the effects of father (A) or mother (B) telomere length (bp) on their offspring telomere length (bp).

Note that parental TL variation was split in two components: the mean TL over all measurements per parent (‘mean TL father or mother’), and the deviation from that mean in each of the years he/she produced offspring sampled that year (‘delta TL father or mother’). The coefficient of mean TL provides information on the effect of between parent variation, while the coefficient of delta TL provides information on variation over the years within parent. See also Fig 3.