ECR Spotlight is a series of interviews with early-career authors from a selection of papers published in Journal of Experimental Biology and aims to promote not only the diversity of early-career researchers (ECRs) working in experimental biology but also the huge variety of animals and physiological systems that are essential for the ‘comparative’ approach. Kayla Garvey is an author on ‘ The role of the heart in the evolution of aerobic performance’, published in JEB. Kayla is a Graduate Student in the lab of Dr Graham Scott at McMaster University, Canada, investigating cardiovascular adaptations in high-altitude deer mice.
Kayla Garvey
How did you become interested in biology?
From a young age I was always really interested in animals and why they live in the environments they do. I was endlessly amazed by the dichotomy of different species, contemplating why some were able to live in the coldest temperatures or at the farthest depths of the ocean. I always spent a lot of time outside and in nature and just kept asking questions about why the ecosystems were the way that they were. I was exposed to biology in elementary school by my 6th grade science teacher when we started to learn the most basic aspects of genetics and how traits are carried down from parents to offspring. I distinctly remember the tongue rolling trait as my whole family can do it but me! But this piqued my interest in heritability, which I didn't know how to describe in words back then, but it kept me interested again, in why and how some people can do things that others can't, even if it's just tongue rolling.
Describe your scientific journey and your current research focus
I took a keen interest in anatomy and physiology in high school and participated in a specialist high-skills major where I was really introduced to how the human body functions and the applications within health care. I always took every opportunity I had to go to the cadaver lab and learn more about the anatomical structure of the human body (I think I ended up going on five field trips during my high school career!). Entering university, I maintained that passion for learning and found myself particularly fascinated with the cardiovascular system. I completed my Honours Bachelor of Science and my undergraduate thesis characterizing the effects of a genetic knockdown of the beta-1 adrenergic receptor in larval zebrafish with Emeritus professor Dr Steve Perry at the University of Ottawa, Canada. I continued to stay on full time for 6 months after my project wrapped up so that I could finish up some experiments and contribute to two primary research articles. This experience really opened my eyes to how spectacular research can be and gave me the opportunity to ask so many more questions about this fantastic organ system. I knew once I finished my undergraduate degree that I wanted to change the model organism and shift my focus onto mammals, which led me to my Master’s supervisor, Dr Graham Scott at McMaster University, and to working on a new model organism, the North American deer mouse! I'm now completing my Master's, which focuses on how hemoglobin oxygen affinity affects aerobic capacity in high-altitude deer mice. These little creatures are so fascinating and provide such a useful tool to continue studying the cardiovascular system.
How would you explain the main findings of your paper to a member of the public?
The ability to consume oxygen efficiently determines an organism's aerobic capacity, which in turn influences locomotion, thermogenesis and overall fitness. The heart is a key determinant for aerobic capacity but the influence of cardiac output versus other downstream traits in the oxygen transport pathway remains contentious. Using North American deer mice native to low altitude and high altitude, we examined the mechanistic basis for adaptive increases in aerobic capacity. We know that highland mice generally have greater aerobic capacity than lowlanders, with corresponding increases in cardiac output, arterial oxygen saturation, blood hemoglobin content and oxygen affinity, tissue oxygen extraction and tissue oxidative capacity. We demonstrate that maximal aerobic capacity depends on the ability of the active tissues to extract oxygen from the blood using fundamental principles of gas exchange. Interactions between cardiac output and blood hemoglobin content also determine circulatory oxygen delivery and affect aerobic capacity, especially at high altitude where an increased number of red blood cells in circulation can increase the viscosity of blood. There may also be functional interactions between cardiac output and tissue oxygen diffusion due to the role of blood flow in determining capillary hematocrit and red blood cell flux. All these functional interactions between cardiac output and various traits across the oxygen transport pathway underlie the adaptive evolution of aerobic capacity.
What do you enjoy most about research, and why?
The thing I love most about research is how it's never done. Once you find the answer to one of your questions, you're left with 10 more! Which provides such exciting avenues for new projects and collaborations. The process of learning new skills, struggling, succeeding and then helping others is one that I love. I also enjoy the ability to communicate with my peers at conferences or even in the lunchroom and get other opinions on the work that I'm doing. When you step out of your own silo as we say, there are some interesting things to try that you may never have thought of on your own.
ID'ing a wild caught mouse during a rainstorm in Kearney, NE, USA, on a field expedition. I'm completely soaked and trying to hide the little mouse in my hand from the rain under the tailgate of the truck!
What is the hardest challenge you have faced in the course of your research and how did you overcome it?
The hardest challenge I've had is learning that not everything will always be perfect and especially that not everything works the very first time you do it. I tend to have high expectations for myself and when I don't meet them, I find it very challenging. However, it's those imperfections and troubleshooting that make this career what it is and leads to great new discoveries. I've really been learning how to roll with the punches and use those challenges to explore new avenues or try new techniques.
What is the most important piece of equipment for your research, what does it do and what question did it help you address?
One of the most important pieces of equipment for my research is the MouseOx® pulse oximeter collars that I use to record heart rate and arterial oxygen saturation in my mice. The collars we use take advantage of dual wavelength spectrophotometry to measure how saturated the blood is with oxygen in the arteries in the mouse's neck. This helps me obtain information on hemoglobin oxygen saturation and heart rate in my mice after they've been treated with different drugs to affect hemoglobin oxygen binding affinity. This is also a funny piece of equipment as you must give the mice a haircut around their neck before you use it because the collars we use must be on the skin of the neck of the mouse. Like how you wouldn't be allowed to have nail polish on when your oxygen saturation is measured with a finger pulse oximeter. So they all just end up having really funny looking haircuts by the end of the trials.
What do you like to do in your free time?
In my free time I love to be outdoors! I'm a huge walker and get 12,000 steps a day every day without fail and I've been doing that for almost 3 years straight. Fresh air really gives me a space to think and refresh my mind. You can also find me with my binoculars looking for birds and waterfowl as I'm becoming a bit of an ornithologist. I'm also an avid New York Times Mini Crossword enjoyer. Everyday, I pop into my New York Times app and do the Connections, Wordle, and Mini Crossword then compare my times with my friends. If I'm not doing any of those things then I'm probably at home with my pets, enjoying their company and giving them some quality TLC.
What's next for you?
I'll be starting my PhD with Dr Graham Scott this fall continuing to work on the cardiovascular system and especially from the standpoint of development in our two populations. I'm also keen on adding a conservation biology spin on my work looking at the impacts of warmer temperatures on movements up the mountains for the mice to stay in their thermoneutral zones and when oxygen may become a limiting factor for that. As we continue to experience the effects of global warming, I think our mice can be a useful tool in contributing to the research on how this will affect small mammals or any species that uses the oxygen transport pathway.
Kayla Garvey's contact details: Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1.
E-mail: [email protected]
