���ӽ紫ý

When Raizel Yankaway applied to ���ӽ紫ý's Ph.D. program in biological sciences, she wasn't convinced it was the right choice just yet. But after participating in a weekend recruitment event, she discovered something special while exploring the campus: a sense of community.

That feeling of belonging, she says, is what became the deciding factor once her acceptance letter came through. “I learned from our program’s grad bootcamp that you can have several circles of support at ���ӽ紫ý that don’t just include your lab or advisor,” says Yankaway, now officially a graduate student in the School of Life Sciences. “Having a solid community to lean on and give back to is important to me.”

It didn't take long for her to discover different groups filled with others who shared similar interests and goals. The Biology Graduate Student Organization (BIOS) connected her with other students in her program, while the Society for Black Scientists has helped her to meet other minority students from different graduate programs who support and inspire each other.

And, now that she's found that support, she's ready to return the favor by inspiring the next generation of science enthusiasts. Yankaway serves as a judge for the Beal Bank USA Southern Nevada Regional Science & Engineering Fair. Hosted by the College of Sciences, the fair showcases science and engineering projects from elementary, middle, and high school students. “Growing up, I never saw someone who looked like me at these types of events, and it can be discouraging,” she says. “Supporting the next generation of scientists is important to me.”

Yankaway's research at ���ӽ紫ý focuses on hibernation physiology in ground squirrels. “Their ability to drastically decrease the activity of important physiological functions makes them seem like a whole different animal during hibernation,” she says. “Learning how different species pull off metabolic depression in entirely different ways has been exciting.”

Here, she fills us in on her research and other favorite experiences while at ���ӽ紫ý — from working in the lab to attending the International Hibernation Symposium.

Tell us about your research.

My research focuses on hibernation physiology in ground squirrels. These small mammals can drop their body temperature to match the environment, usually about 4℃ (39.2° F) and sometimes as low as -2.9℃ (26.78° F). They can also decrease their respiratory rate, heart rate, and other homeostatic processes to negligible numbers, conserving energy throughout the harsh winter months. I'm also looking at how ambient temperature affects the regulation of the different states of hibernation.

Torpor is the deep sleep-like state that characterizes hibernation. And the transitions into and out of torpor are what I find fascinating. During these phases, the animals decrease/increase the activity of critical life functions within hours. My goal is to understand how these transitions change as a function of ambient temperature.

Interestingly, there is a long-standing bias in hibernation research toward cold-climate species. However, we now know that hibernation likely originated in the tropics. This raises important evolutionary questions: If hibernation emerged in regions where cold and food scarcity aren’t major pressures, then why did it evolve in the first place? And how does that shift our broader understanding of hibernation?

To explore these questions, our lab maintains a colony of the common tenrec (Tenrec ecaudatus), a species we consider to be reminiscent of an ancestral placental mammal. Tenrecs do hibernate in temperate climates. By comparing the tenrec’s unique hibernation patterns to the more “modern” strategies seen in ground squirrel hibernation, we’re working to refine our understanding of how hibernation evolved.

How could your research have an impact on the general public? 

Many people don’t realize that ground squirrel hibernation can serve as a valuable model for studying several common human conditions. For example, ground squirrels naturally develop insulin resistance as they prepare for hibernation, but appear to reverse it during the hibernation season, offering potential insights into managing or even reversing type 2 diabetes. Their ability to rapidly rewarm from torpor to normal body temperatures could inform better treatment strategies for conditions like hypothermia and ischemia-reperfusion injury or the damage that occurs when blood flow is restored to previously oxygen deprived tissues. 

What excites you about the research you are doing?

Figuring out the “why.” For example, we still don’t fully understand why hibernators have an interbout arousal – a brief period of spontaneous rewarming during which a hibernating animal returns to normal body temperature after a period of torpor. Rewarming alone accounts for roughly about 70% of the total energy used during hibernation season, so we know it’s important, but what is the purpose? Some hypotheses include clearing metabolic waste, repaying sleep debt, or repairing cellular damage, but none have been definitively supported by enough evidence. 

What are you working on next?

I am beginning a project that was started earlier in the lab, where we’re interested in creating a “damage” panel for the tenrecs. These animals may face several stressors during hibernation, including temperature, oxidative, and immune stress. Can we see clear patterns in how these animals deal with these stressors? Is anything temperature or state-dependent? I’m excited to explore if/how the responses might differ from what we know about ground squirrels.

What are you most proud of in your academic career so far?

Getting through my comprehensive exams is definitely one of my highlights, but going to the International Hibernation Symposium and presenting a poster is one of the things of which I am most proud. Attending a conference geared specifically toward your area of research is so exciting because you get to meet and talk to the researchers from all the papers you’ve been reading. Even though it was intimidating to explain my research to some of the researchers there, they all gave great advice and feedback on my data and presentation.