Graduate Thesis Defense

Name:Krysta Yancey
Title:Shining light on hibernator genomes: Using radiation to reveal DNA damage and repair dynamics in Arctic ground squirrels
Date:Thursday, 19 April 2018
Location:Akasofu Bldg, rm 501 (IARC)
Major Professor:Andrej Podlutsky


Mammalian hibernation is characterized by dynamic changes in metabolism and body temperature; it may be sustained for up to nine months. The majority of hibernation is spent in torpor, a dormant state, but is regularly interrupted by brief periods of activity referred to as interbout arousal. Thermogenesis begins in vascularized fat, brown adipose tissue, and ends with whole-body shivering until the animal reaches a normal body temperature around 36 °C. Interbout arousal is usually less than a day long and is commonly thought to be necessary for maintenance and repair of tissues, in addition to the cycling and replenishment of metabolites. These torpor-arousal cycles, while physiologically extreme, do not drastically impact the health of hibernators, rather hibernators are recognized for their longevity and resistance to a spectrum of stresses, especially ischemia/reperfusion and the brain damage that typically follows. However, it remains unknown how the process of hibernation challenges genome stability and the basic molecular mechanisms of DNA repair. Therefore, we begin with a review on current knowledge of genome maintenance in the context of hibernation, distinguishing it from other similar and often correlated conditions like hypothermia. Then, we present the first cellular and molecular study to be conducted on DNA damage and repair dynamics in a hibernator using the Alaskan Arctic ground squirrel. Our results indicate that through status-specific combinations of strategies for preventing DNA damage and efficient DNA repair, paired with anti-apoptotic environments, hibernators can avoid genome instability during torpor-arousal cycles. The unique suite of adaptations necessary to endure torpor-arousal cycles may help explain the longevity and radio-resistance that are often associated with hibernating species.

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