DISSERTATION RESEARCH: An Investigation of the Evolution of Telomere Regulation and Longevity

Iowa State University, Ames IA

Investigators

Abstract

This research will investigate the underlying physiological and molecular mechanisms responsible for the wide variation in life spans of different species. One potential mechanism underlying adaptive variation in species maximum lifespan is regulation of telomere dynamics. Telomeres cap the ends of all eukaryotic chromosomes and function in protecting chromosomes and aiding in the completion of duplication. Telomeres shorten with each cell division, however, because of physical limitations of DNA polymerase. Once telomeres shorten to a critical length, cells enter replicative senescence, so while these cells are metabolically active they can no longer divide. Replicative senescence has been suggested as a causal agent of aging and age-related diseases. Previous research has shown that species with longer lifespans lose telomeric repeats at a slower rate than species with shorter lifespans. This suggests that selection may adjust the rate at which telomeres shorten to modify lifespan. This research involves a comparative analysis of 17 bird species that vary in maximum lifespan from 5 to 44 years. It will foster large-scale collaboration between many scientists and promote undergraduate and graduate training in the biology of aging. The results will determine whether telomere regulation has jointly evolved with species maximum lifespan. If so, it will support the hypothesis that telomere regulation acts as a molecular mechanism to adjust lifespan. This project will offer valuable insight into the evolution of mechanisms that influence lifespan.