Among-population variation in telomere regulatory proteins and their potential role as hidden drivers of intraspecific variation in life history

Biologists aim to explain patterns of growth, reproduction, and ageing that characterize life histories, yet we are just beginning to understand the proximate mechanisms that generate this diversity. Existing research in this area has focused on telomeres but has generally overlooked the telomere’s most direct mediator, the shelterin protein complex. Shelterin proteins physically interact with the telomere to shape its shortening and repair. They also regulate metabolism and immune function, suggesting a potential role in life history variation in the wild. However, research on shelterin proteins is uncommon outside of biomolecular work.
Intraspecific analyses can play an important role in resolving these unknowns because they reveal subtle variation in life history within and among populations. Here, we assessed ecogeographic variation in shelterin protein abundance across eight populations of tree swallow (Tachycineta bicolor) with previously documented variation in environmental and ..., Study populations: Data were collected from 8 populations in the eastern United States, spanning nearly 10 degrees of latitude (Table 1, Fig 2A): Ithaca, New York (42.28°N, 76.29°W); Amherst, Massachusetts (42.22°N, 72.31°W); Linesville, Pennsylvania (41.65°N, 80.43°W); Bloomington, Indiana (39.17°N, 86.53°W); Lexington, Kentucky (38.11°N, 84.49°W); Knoxville, Tennessee (35.90°N, 83.96°W); Davidson, North Carolina (35.53°N, 80.88°W); and Santee, South Carolina (33.49°N, 80.36°W). These populations do not represent the entire breeding range of this species and in particular, do not extend to the northern edge in Canada and Alaska. All methods were approved by institutional IACUCs and conducted with appropriate state and federal permits.
Sampling of nestlings: Nest boxes were monitored for hatch dates, but in cases where hatch dates were missed (e.g., due to weather or COVID-related staffing shortages), hatch dates were estimated using existing growth curves (McCarty, 2001; Wolf et al., 2..., , # Among-population variation in telomere regulatory proteins and their potential role as hidden drivers of intraspecific variation in life history

We assessed ecogeographic variation in shelterin protein abundance across eight populations of tree swallow (Tachycineta bicolor) with previously documented variation in environmental and life history traits. Using blood gene expression of four shelterin proteins in 12-day old nestlings, we tested the hypothesis that shelterin protein gene expression varies latitudinally and in relation to both telomere length and life history.

This dataset includes the following information from nestlings sampled across eight populations: # siblings, age, molecular sex, morphology, relative telomere length, and relative gene expression for four shelterin protein genes.

## Description of the data and file structure

In the excel file, each row corresponds to an individual nestling. Because of the nature of field work, each variable of interest does have ...