Date of Award
Spring 5-10-2025
Document Type
Honors Thesis
Department/Major
Biology
First Advisor
Dr. Andrea Liebl
Second Advisor
Dr. Mark Bouska
Third Advisor
Dr. Bernard Wone
Keywords
Environment, Chestnut-crowned babbler, telomeres
Abstract
Telomeres, repetitive nucleotide sequences at the ends of chromosomes, are vital in maintaining genomic integrity. Because degradation of these structures has been linked to oxidative stress, inflammation, and metabolic demands, they are also recognized as biomarkers for biological aging, lifespan, and physiological stress. This study investigates the ecological and physiological factors influencing telomere length changes in adult chestnut-crowned babblers (Pomatostomus ruficeps), a cooperatively breeding bird native to the arid and semi-arid zones of southeastern Australia. This species offers a valuable system for exploring how ecological pressures shape life history strategies due to the harsh environmental factors and social relationships they experience. Utilizing quantitative real time PCR (qRT-PCR) on blood samples collected across two consecutive years, relative telomere length (RLTL) was quantified in 12 individuals (29 samples total). The RLTL data was then used to determine the change in telomere length for an individual across a year span. Environmental variables—including mean maximum temperature and total rainfall over both the 3 months prior to the breeding season and the year between samples—along with group size and sex, were tested to assess their relationship with telomere length changes. I found a significant positive relationship between average maximum temperatures in the year between the two samples and telomere changes, contradicting the fields’ current understanding that chronic exposure to elevated temperatures imposes physiological stress that accelerates cellular aging. Although rainfall showed a non-significant trend with telomere lengthening, this may be a result of simultaneous reductions in breeding in years without rain. Similarly, no significant relationships were found with sex or group size, though these factors have been linked to telomere variation in other avian species. Future research looking at oxidative stress, glucocorticoid levels, shelterin complex proteins, and direct measures of reproductive investment could further reveal the links between telomeres and environmental adaptation in cooperative avian systems.
Recommended Citation
Langston, Carson L., "THE EFFECTS OF ENVIRONMENTAL, BIOLOGICAL, AND SOCIAL FACTORS ON TELOMERE LENGTH IN CHESTNUT-CROWNED BABBLERS" (2025). Honors Thesis. 387.
https://red.library.usd.edu/honors-thesis/387
Comments
There are only 3 spots to but thesis advisors, but I had 4 committee members: Dr. Andrea Liebl, Dr. Mark Bouska, Dr. Bernard Wone, and Dr. David Swanson.