Hidden causes of variation in offspring reproductive value: negative effects of maternal breeding age on offspring telomere length persist undiminished across multiple generations

Offspring of older breeders frequently show reduced longevity, which has been linked to shorter offspring telomere length. It is currently unknown whether such telomere reduction persists beyond a single generation, as would be the case if germline transmission is involved. In a within-grandmother, multi-generational study using zebra finches, we show that the shorter telomeres observed in F1 offspring of older mothers is still present in the F2 generation even when the breeding age of their F1 mothers is young. The effect was substantial - 43% shorter telomeres in grandoffspring from the ‘grandmother old at breeding’ line compared with those from the ‘grandmother young at breeding’ line. Shorter telomeres at fledging in this species are associated with a reduction in lifespan. Our data demonstrate the need to look beyond a single generation to explain inter-individual variation in ageing rates, and thereby variation in optimal allocation of age-specific reproductive effort.
, , , # Hidden causes of variation in offspring reproductive value: negative effects of maternal breeding age on offspring telomere length persist undiminished across multiple generations

by Valeria Marasco, Winnie Boner, Kate Griffits, Shirley Raveh, & Pat Monaghan

## Data Description

Telomere length: T/S ratio (Telomere repeat copy number / GAPDH)

Body mass: grams

### Data1_ELE-00395-2024.csv

dataset to analyse effect of grandmother (F0) age at breeding on grandoffspring (F2) body mass and telomere length at 30 days of age. Description of variables (from left to right):

* F2 Ring: id F2 bird
* Gen: Generation of birds (i.e., F2, F2.2)
* TEL: Telomere length at 30-day sampling
* D30_Mass: Body mass at 30-day sampling
* Sex: sex of F2 bird
* Hatch_Nest: nest id of F2 bird
* Chick_Num: hatching order of F2 bird
* Cluth_site: size of the clutch from which F2 bird originates
* ID_mother_of_F2: mother id of F2 bird

- TEL_Mother_of_F2: telomere length at 30-day sampling of the mother of F2...,