How do organisms cope with uncertainty in their environment? Understanding how organisms cope physiologically with naturally variable environments will be important for predicting organismal responses, including those in humans, to increasingly unpredictable environments characterized by frequent extreme weather events like droughts and floods. And since coping mechanisms themselves, short-term physiological and behavioral responses, respond to environmental variation over longer time periods, a comparative approach is needed to fully understand how organisms have historically responded to climatic uncertainty. To determine how vertebrates adapt to and cope with environmental variation at the physiological and molecular level, this study will simultaneously explore patterns of genetic and epigenetic variation in genes of birds that underlie the stress response and the entire genome across an ecological gradient in Kenya, and then relate this variation to patterns of gene expression in naturally variable and experimentally-controlled climates. This study will train high school students, undergraduates, and graduate students, particularly those from underrepresented groups, in the field and lab. Training will emphasize cutting-edge, integrative tools that are transferable across disciplines. Researchers will work closely with a grassroots Kenyan conservation organization to educate rural schoolchildren on conservation and wildlife through a series of teaching modules and public representations. Finally, researchers will present the results of their work locally around New York City and in popular articles aimed at a diverse audience.
One of the primary ways that vertebrates cope physiologically with environmental variability is through changes in the hypothalamo-pituitary-adrenal (HPA) axis, the neuroendocrine system that controls reactions to stress. The HPA axis encompasses a cascade of hormones, receptors, and other molecules, each of which may respond to different types and timescales of environmental variation. Although understanding how the HPA axis responds to environmental variability is important for determining how organisms will cope with environmental uncertainty because it is one of the first ways that vertebrates respond to environmental stressors, many other physiological, endocrine, and molecular pathways are also impacted by environmental stressors. Therefore, a genome-wide approach that links molecular mechanisms and adaptive genetic and epigenetic variation more broadly to physiological function will be necessary to understand how animals adapt to and cope with environmental uncertainty. The objective of this study is to determine how environmental variation influences adaptive genetic (DNA sequence) and epigenetic variation (DNA methylation), gene function (mRNA expression), and physiological responses (hormone activity) to shape particular phenotypes in populations of free-living superb starlings (Lamprotornis superbus) sampled across a broad-scale ecological gradient in sub-Saharan Africa encompassing some of the most unpredictable climatic zones in the world. Building upon long-term data in African starlings, and using a series of newly-established populations along an ecological gradient in Kenya, this work will allow researchers to begin to understand how environmentally-induced selection pressures shape the molecular mechanisms, adaptive evolutionary responses, and coping strategies that vertebrates use to live with environmental uncertainty.
