ECR Spotlight – Brynne Duffy Free

Brynne Duffy

How did you become interested in biology?

I've been fascinated by biology for as long as I can remember. As a kid, I was relentlessly teased for my obsession with whales, but that never dampened my curiosity. I was captivated by their ability to perform deep dives while holding their breath for extended periods. That early fascination eventually led me to take a marine biology field course at the Huntsman Marine Science Center, Canada, during my undergraduate studies. At the time, I had no idea that the course instructor, Dr Jim Staples, would one day become my graduate supervisor. He introduced me to the metabolic suppression of hibernating ground squirrels – animals that, in some ways, aren't so different from diving whales but are much easier to house in the basement of the biology building at Western University. Looking back, it's incredible how a childhood passion shaped my academic journey and led me to where I am today.

Describe your scientific journey and your current research focus

My scientific journey began in earnest during that marine biology field course, where I became close with both Teaching Assistants, one studying cold-tolerant arachnids and the other researching lipid metabolism in migratory birds. Their encouragement made me realize that I, too, could belong in research. Inspired, I started volunteering in Brent Sinclair's lab at the University of Western Ontario as a ‘spider wrangler’, helping race black widows up wooden dowels at various temperatures and helping to measure their supercooling points and lower lethal temperatures.

A few years later, I conducted my own honours thesis in the same lab, investigating how cold exposure affects memory formation and retention in pond snails. By then, I knew I wanted to pursue a research career but was eager to shift toward mammalian physiology and molecular mechanisms. That led me back to Jim Staples’ lab, where I developed my current research focus on mitochondrial metabolism and reactive oxygen species (ROS) in hibernating 13-lined ground squirrels.

Hibernation fascinates me because of the dramatic physiological transitions between deep torpor and interbout arousals. During arousal, heart rate, respiration and, in this study, arterial oxygen saturation increase significantly. More oxygen, especially when rapidly introduced, often leads to excess ROS production, which can be harmful. However, ground squirrels survive dozens of these cycles each hibernation season and even exhibit remarkable resistance to ischemia–reperfusion injuries, similar to those seen in strokes or heart attacks.

To justify my thesis, I needed to confirm that arousals in 13-lined ground squirrels were indeed re-oxygenation events – something that was previously assumed based on their heart rates increasing from 4 to more than 350 beats per minute. Fortunately, I met another wonderful researcher, Dr Catie Ivy, who helped me borrow a MouseOx^® from her former supervisor and trained me in its use. Catie taught me technical skills and so many things, and importantly, she reminded me to step back from the mitochondria to see the bigger picture at the whole-animal level.

How would you explain the main findings of your paper to a member of the public?

Our study found that 13-lined ground squirrels experience extreme changes in oxygen levels during rewarming from hibernation, something that would be dangerous for most animals. Early in arousal, these squirrels had oxygen levels of just 35% in the blood going to their heads, which is far below what would be considered a medical emergency in humans. Even compared with other hibernators, this is the lowest oxygen saturation that we know of. Yet, when the 13-lined ground squirrels do ‘wake up’, their oxygen levels shoot back up to 87%, a massive 250% increase. For most animals, such drastic oxygen fluctuations would cause serious tissue damage, similar to what happens during a stroke or heart attack. But these squirrels go through this cycle at least 15 times every winter without apparent harm. Understanding how they protect their bodies from this stress could one day help scientists develop new treatments for human diseases related to oxygen deprivation, such as strokes and heart attacks.

What do you enjoy most about research, and why?

Curiosity has always come naturally to me, and it's one of the things that makes me a good researcher. Rather than asking broad why questions – where the answer often feels like ‘because… natural selection’ – I'm drawn to figuring out how things work. I enjoy forming hypotheses and predictions to explain natural phenomena, especially when it comes to unique animal traits. That's why comparative physiology is so captivating to me: we can seek out animals that do extraordinary things and try to uncover the mechanisms behind them. The pursuit of knowledge itself fuels me, and if my findings one day lead to advances that help humans, that's just an added bonus.

What is the most important lesson that you have learned from your career so far?

Science is challenging, but it's much more rewarding when you surround yourself with supportive colleagues. Some of my most valuable research experiences happened because of friendships, whether it was learning a new technique, borrowing equipment or simply having someone to troubleshoot with. Collaboration, rather than competition, leads to better science and a more enjoyable career. Kindness fosters strong networks, and those connections can open doors you never expected. At the end of the day, the research is important, but the people you work with make all the difference.

What's next for you?

My immediate focus is to finish my thesis. I'm close, and I have a strong support system in place to get me over this last academic hurdle of my doctorate. Once that's done, I plan to build my teaching experience while searching for the right postdoctoral position to continue in research. One of my biggest challenges is that I can be interested in just about anything. I love asking questions, exploring new ideas and learning new skills to add to my growing molecular toolkit. That said, I want to make strategic choices that will set me up for a career I'll be proud of and truly enjoy. I've come to appreciate that securing funding is a big part of feeling secure in research. So, I'm looking for projects that not only excite me but also provide opportunities for multiple grant applications. Currently, I am mulling over the idea of studying animal physiology with a direct link to clinical application. Ultimately, I want to find a postdoc that will help me grow as both a scientist and an educator – and of course, if you're hiring, I'd love to chat, and my email is provided somewhere on this ECR Spotlight; thank you, JEB!