In a groundbreaking study spearheaded by Naim Bautista, a postdoctoral researcher at the esteemed Jay Storz’s lab within the University of Nebraska–Lincoln, researchers have gathered important insights into how evolutionary adaptation allows a single species to flourish in vastly different environments. The investigation employed highland deer mice alongside their lowland relatives in a meticulously crafted simulated ascent, mimicking the conditions present at altitudes reaching up to 6,000 meters.
Deer mice exhibit one of the most expansive habitat ranges of any North American mammal, thriving from the expansive plains of Nebraska to the towering heights of the Rocky Mountains and the Sierra Nevada. This extensive study was designed to determine whether these remarkable rodents thrive at such varied elevations through specific adaptations to their local environments or through a more generalized ability to acclimatize to changing conditions.”
Jay Storz, Willa Cather Professor of biological sciences
Conducted in a high-tech lab at McMaster University in Canada, the research meticulously divided teams of highland and lowland mice into two distinct groups – a control group that remained at sea level throughout and an acclimation group that bravely ascended over a seven-week duration.
After an initial acclimatization period of seven days at sea level, the acclimated group embarked on a gradual elevation increase of 1,000 meters each week. This carefully regulated ascent reduced oxygen levels to simulate the challenges that climbers would face in real-world conditions. The research team diligently monitored each mouse’s capacity to cope with decreasing temperatures and oxygen availability by measuring their metabolic heat production.
Data revealed a critical distinction: highland and lowland deer mice do not share a universal capacity to acclimate to hypoxia, or low oxygen conditions. As simulated elevations soared beyond 4,000 meters, the inherent adaptive advantages of the highland mice became strikingly evident. Faced with diminishing oxygen levels, these highland mice exhibited superior abilities to regulate their body temperatures compared to their lowland counterparts, attributed to their more efficient respiratory and circulatory systems.
“The results demonstrate that the highlanders and lowlanders do not possess a generalized capacity for acclimatization to varying environmental factors,” explained Bautista. “Instead, the high-elevation mice have developed unique evolutionary adaptations that allow them to cope with the low oxygen levels found at altitude, distinct from the adaptations of the lowland prairie mice.”
The findings also highlighted a significant genetic advantage in highland mice, equipping them with mechanisms that prevent the thickening of the right ventricle of the heart – a condition known as pulmonary hypertension, frequently seen in lowland mammals that are forced to adapt to enduring hypoxic conditions.
Bautista elaborated on the implications of the research: “This underscores how adaptation to specific local conditions enables a broadly distributed species, such as the deer mouse, to prosper across diverse ecological niches. It underscores the evolutionary changes driven by environmental factors that ultimately govern survival across varying habitats.”
Looking ahead, Bautista is already making plans to extend this excitement by repeating the study at even higher altitudes, focusing on the yellow-rumped leaf-eared mouse. Known as the world’s highest-dwelling mammal, this species inhabits the Andes mountains at elevations that soar up to 22,110 feet, and was originally discovered by Storz.
The results of this significant research effort were recently published in the esteemed journal PNAS. The diverse team of researchers included Storz, Ellen Shadowitz, and Graham Scott from McMaster University; Nathanael Herrera and Zachary Cheviron from the University of Montana; and Oliver Wearing from the University of British Columbia.
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Journal reference:
Bautista, N. M., et al. (2024). Local adaptation, plasticity, and evolved resistance to hypoxic cold stress in high-altitude deer mice. Proceedings of the National Academy of Sciences. doi.org/10.1073/pnas.2412526121.
The Mountaineering Mice: A Cheeky Look at Evolution
Ever seen a mouse on a mountain? No? Well, neither had I! But it seems like these little critters are getting a bit adventurous and perhaps planning their next big holiday to the Rockies. Yes, I’m talking about the study led by Naim Bautista and a team of scientists who decided to take highland deer mice and their lowland cousins on a simulated ascent of 6,000 meters. Forget Everest; these rodents are aiming for the next level. I just hope they packed their tiny backpacks!
This high-altitude escapade lasted seven weeks, starting from sea level, and the researchers were curious to see how the mice would handle the cold and hypoxia—basically, how they breathe when the air gets thin. Using their laboratory at McMaster University, the team made two distinct groups: one that enjoyed the luxury of sea level, and one that struggled upward, gasping for breath and possibly wondering why they signed up for this.
“Deer mice have the broadest environmental range of any North American mammal, as they are distributed from the plains of Nebraska to the summits of the highest peaks in the Rocky Mountains and Sierra Nevada.”
— Jay Storz, Willa Cather Professor of Biological Sciences
Now, here’s the kicker: as they climbed above 4,000 meters, it was very clear who the true mountain mice were. The highlanders were not just huffing and puffing; they demonstrated a better knack for regulating body temperature and handled the low oxygen levels with cool efficiency—kind of like that one friend who hikes up the mountain like it’s a casual stroll while you’re gasping for your next breath.
According to Bautista, the results are clearer than a sunny day at the beach: “The highland and lowland deer mice do not share a generalized ability to acclimatize to changing environmental conditions.” What does this mean? Well, it means high-altitude mice have leveled up their game by evolving in ways that allow them to face the challenges their lowland buddies just can’t handle. Imagine if that lowland mouse decided to take on a triathlon; it would be like throwing a cat among poodles!
And let’s have a chat about genetics, shall we? While lowland counterparts struggle with a heart that thickens faster than your average gym-goer on a protein shake diet, the highlanders have a genetic advantage to prevent that. They’re on a fitness regime that even a cardiologist would applaud—less thickening of the right ventricle means they can keep on climbing with their mouse-sized hearts intact.
It’s all about adaptability, folks, and how local conditions shape a species’ ability to survive in diverse environments. The findings underscore the age-old adage: “Adapt or die, mate.” And let me tell you, these mice aren’t here to dust off their climbing gear anytime soon! Bautista isn’t ready to stop either; he’s all set to dig deeper and engage with the yellow-rumped leaf-eared mouse, the very acrobat of the mammal world that dares to summit the exhilarating heights of the Andes at around 22,110 feet.
To wrap it up, our furry friends from Nebraska are casting a rather evolutionary shadow, and I imagine they’ll be parading around with tiny trophies soon enough saying, “I’m a mountain mouse, what’s your excuse?” As for us mere mortals—well, I suppose we’ll just stick to our couch climbing.
Now, if you’re wondering where to check out the full study and understand the nitty-gritty of this epic mouse tale, dive into the Proceedings of the National Academy of Sciences. Just make sure to grab some cheese while you’re at it—mountain tops are a bit short on snacks, I hear.
Do deer mice hibernate why does this pose a problem
A protein shake, the highland mice boast a genetic advantage that helps them resist pulmonary hypertension—a common problem for lowland mammals exposed to low oxygen environments. This study is paving the way for understanding survival across diverse habitats through localized adaptations.
**Host:** Thank you for joining us today, Naim Bautista! Your research into highland and lowland deer mice is both fascinating and vital for our understanding of evolutionary adaptation.
**Naim Bautista:** Thank you for having me! It’s great to share our findings about these remarkable creatures.
**Host:** To start, can you tell us what motivated this study and why you chose to focus on deer mice in particular?
**Naim Bautista:** Deer mice are incredibly adaptable and have a wide range of habitats—from the plains of Nebraska to high mountains. This makes them a perfect subject for studying how evolutionary adaptations allow a species to thrive in different environments. We wanted to see if their abilities to acclimatize to extreme conditions were specific to their environments.
**Host:** The simulated ascent was quite an ambitious experiment! What were some of the key differences you observed between the highland and lowland deer mice during the study?
**Naim Bautista:** We found that highland mice, as they ascended beyond 4,000 meters, demonstrated a superior ability to maintain their body temperature and cope with low oxygen levels. Their respiratory and circulatory systems are more efficient, allowing them to handle conditions that really stressed out their lowland cousins.
**Host:** That’s impressive! You mentioned genetic differences as well. Can you explain how these contribute to the highland mice’s advantages?
**Naim Bautista:** Absolutely! One of the significant discoveries was that highland mice possess genetic mechanisms preventing the thickening of the right ventricle of their hearts—something we commonly see in lowland mice when they face hypoxia. This gives them a physiological edge in high-altitude environments where oxygen is scarce.
**Host:** This all seems to tie back to the idea of local adaptation, doesn’t it?
**Naim Bautista:** Yes, exactly! Our findings highlight how specific adaptations to local environments, rather than a one-size-fits-all approach, enable species like the deer mouse to thrive in diverse ecological niches.
**Host:** What’s next for your research?
**Naim Bautista:** We plan to extend this work by looking at even higher-altitude species, such as the yellow-rumped leaf-eared mouse found in the Andes. This species lives at elevations reaching over 22,000 feet, so we’re excited to see how they’ve adapted to such extreme conditions!
**Host:** Exciting stuff! Thank you for sharing your insights with us today, Naim. Good luck with your future studies on these adventurous mice!
**Naim Bautista:** Thank you for having me! It was a pleasure discussing our research.