Doctoral Dissertation Research: Gene Expression and Physiologic Extremes in Primate Hibernation

Duke University, Durham NC

Investigators

Abstract

Hibernation is a seasonal response that some species use to evade energetic demands posed by their environment. Hibernation is characterized by physiologic extremes that would be fatal to non-hibernating species, yet hibernators experience these extremes on an annual basis without harmful effects. Among primates, hibernation is only observed in the dwarf lemurs of Madagascar. Previous work suggests that hibernation is activated not by a set of genes unique to hibernators, but by selective expression of genes that are present in all mammals. This view raises multiple questions, including: Are the physiological processes associated with hibernation shared among all mammalian hibernators (e.g., ground squirrels, bats, bears), or does primate hibernation represent a specialized form of this behavior? Do all mammals, including humans, have the genetic capacity for hibernation? If so, how can we use this information for critical biomedical applications, such as emergency medicine or space travel? Broader impacts also include development of new research collaborations and significant science education and public outreach efforts. Transcriptome sequencing will be used to identify and quantify genes that are differentially expressed in white adipose tissue from differing physiological states associated with hibernation in 3 dwarf lemur species: one species of captive dwarf lemur (C. medius), and two species of free-ranging dwarf lemurs in Madagascar (C. crossleyi and C. sibreei). This is the first investigation of the genetic control of hibernation in a primate and therefore, this study has implications for understanding hibernation physiology at the most fundamental level. Revealing insights into how primate hibernators successfully display physiologic extremes without morbidity or mortality will have potential applications for biomedical research, and is relevant to the fields of comparative physiology, primate behavior, and evolutionary biology.