Analysis of the first fully-sequenced genome of the Siberian hamster shows how these small, seasonal breeders adapt their bodies and energy usage to survive the winter.
The research, published this week in the Proceedings of the National Academy of Sciences, also includes transcriptome analysis of gene expression in the brain during both summer and winter conditions, which reveals the cascade of signals that prepare the hamster for winter, triggered by decreasing day length.
The Siberian hamster (Phodopus sungorus) is a model organism for studying seasonal biological rhythms. They breed during the spring and early summer, but as fall approaches and day length shortens, their bodies change dramatically. The hamsters lose almost half their body weight, mostly through fat, and limit food intake by 30 to 40%. They don’t hibernate, but modestly reduce their body temperature during the daytime to conserve energy. Their fur thickens and changes color to stark white, and they become infertile until they begin reversing course to prepare for the next breeding season.
The new study shows that shifting day length alone was enough to trigger these changes, regardless of temperature or how much food is available.
“We hope this will be a tool for discovery and more research on a really interesting biological puzzle, which is how organisms navigate the energetic landscape of nature over the course of a year,” said Brian Prendergast, PhD, professor of psychology at the University of Chicago and one of the authors of the study.
The research is a collaborative project with senior author Tyler Stevenson, PhD, a former postdoctoral fellow in Prendergast’s lab now on the faculty at the University of Glasgow. Stevenson worked with Riyue Bao, PhD, from the UChicago Center for Research Informatics bioinformatics group, to assemble and analyze the hamster genome and transcriptome, or the RNA molecules expressed by its genes, to understand the activity of these genes in the brain under both summer and winter conditions.
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