A time capsule written in ancient feces and frozen in permafrost
From the frozen burrows of the Yukon to the cellular machinery of the living human body, a recent episode of CBC's Quirks & Quarks traced the long arc of biological discovery — reminding us that life keeps its secrets in unexpected places, from ancient squirrel droppings to the quiet mutations accumulating in our own cells. Scientists are learning to read these hidden records not merely as curiosities, but as maps toward a medicine that works with the grain of life rather than against it. The past, it seems, is not only preserved in ice — it is still shaping what we might become.
- Gold miners in the Yukon kept unearthing ancient squirrel burrows, and inside them, a biomolecular archaeologist found DNA up to 700,000 years old — a frozen census of Ice Age life hiding in fossilized feces.
- Woolly mammoths, American cheetahs, steppe bison, and hundreds of vanished plant species were all encoded in those ancient droppings, turning humble squirrel waste into one of the richest ecological archives ever discovered.
- Meanwhile, axolotls, zebrafish, and mice are quietly doing something humans cannot — regrowing entire limbs — and researchers have now begun identifying the specific genes that make this possible.
- Every human cell is mutating constantly, and while some errors cause cancer, scientists are now asking whether others might be harnessed as tools for healing rather than treated only as threats.
- Across all four stories, the episode traced a single underlying tension: the gap between what biology can do and what medicine has yet to learn to ask of it.
On a recent episode of Quirks & Quarks, host Bob McDonald led listeners through four corners of contemporary science, each one revealing something unexpected about how life stores, loses, and rebuilds itself.
The first story began in the Yukon, where gold miners digging through permafrost kept uncovering ancient ground squirrel burrows still containing fossilized feces. Biomolecular archaeologist Tyler Murchie of the Hakai Institute recognized the potential in these deposits and extracted DNA dating back between 30,000 and 700,000 years. What emerged was astonishing: genetic traces of woolly mammoths, steppe bison, ancient horses, American cheetahs, grasshoppers, and hundreds of plant species — an entire vanished ecosystem, inadvertently preserved by the digestive systems of small rodents. The findings were published in Nature Communications.
The second segment turned to regeneration. Axolotl salamanders, zebrafish, and mice can regrow entire limbs — a capacity humans lost somewhere in our evolutionary past. Josh Currie of Wake Forest University has been mapping the specific genes behind this ability in axolotls, and his team's work, published in PNAS, raises the possibility that these genetic instructions could one day inform regenerative medicine for humans. The research is early, but the implication is profound: the biological knowledge to repair what we consider permanent damage may already exist in other animals.
The episode also revisited a 1986 archive interview in which Isaac Asimov spoke with then-host Jay Ingram about robots, artificial intelligence, and space exploration — ideas that have since moved from speculation to reality.
The final segment examined something unfolding inside every living person. Our cells mutate constantly, copying genetic instructions imperfectly from birth to death. Most errors are silent; some cause disease. But science journalist Roxanne Khamsi, in her new book Beyond Inheritance, documents how researchers are beginning to see these mutations not as enemies but as potential tools. The genome you were born with is not the one you carry today — and learning to work with that difference, rather than simply fear it, may define the next frontier of medicine.
On a recent episode of Quirks & Quarks, the CBC's long-running science program, host Bob McDonald guided listeners through four distinct corners of contemporary research—each one revealing something unexpected about how life works, how it changes, and how it might be engineered to work better.
The first story began in the Yukon, where gold miners digging through permafrost kept stumbling upon something unusual: ancient burrows left behind by ground squirrels, many of them still containing fossilized feces. Tyler Murchie, a biomolecular archaeologist at the Hakai Institute, recognized the scientific potential in these preserved waste deposits. His team extracted and analyzed DNA from the feces, recovering genetic material that dated back between 30,000 and 700,000 years—some of the oldest DNA ever successfully recovered. What made the discovery remarkable was not just the age of the material, but what it contained. Trapped within those ancient droppings were genetic traces of a menagerie of Ice Age creatures: woolly mammoths, grasshoppers, steppe bison, ancient horses, American cheetahs, and hundreds of plant species. The squirrels, it turned out, had been inadvertent archivists, their digestive systems preserving a snapshot of entire ecosystems that vanished millennia ago. The research was published in Nature Communications.
The second segment shifted focus to a different kind of biological puzzle: regeneration. Axolotl salamanders, mice, and zebrafish all possess an ability that humans largely lost somewhere in our evolutionary past—the capacity to regrow entire limbs. Josh Currie, a biologist at Wake Forest University in North Carolina, leads a lab studying the Mexican axolotl, and his team has made progress identifying the specific genes responsible for this regenerative feat. The work, published in the Proceedings of the National Academy of Sciences, suggests that understanding these genetic instructions could eventually open pathways toward regenerative medicine in humans. The research remains early, but the possibility is tantalizing: if we could unlock what these animals know, we might one day repair injuries that currently leave permanent scars.
The third story took a step backward in time, to 1986, when the legendary science fiction writer and scientist Isaac Asimov sat down with then-host Jay Ingram to discuss robots and artificial intelligence. Asimov had spent decades exploring the relationship between humans and machines in his novels and short stories, and his ideas were gaining fresh relevance as real-world AI systems became increasingly sophisticated. The archive interview also touched on space exploration, including early discussions about building an international space station—a project that would eventually become reality.
The final segment addressed something happening inside every human body, right now, at the cellular level. Our cells are constantly mutating, copying their genetic instructions imperfectly from the moment we're born until the moment we die. Most of these copying errors go unnoticed. Some are catastrophic—they can trigger cancer or other diseases. But many are neutral, and some may actually be beneficial. Canadian science journalist Roxanne Khamsi has explored this landscape of cellular mutation in her new book, Beyond Inheritance: Our Ever-Mutating Cells and a New Understanding of our Health. Her work documents how scientists are beginning to harness these mutations not as enemies to be defeated, but as tools that might improve human health. The genetic instructions you inherit from your parents are not the same ones you carry at the end of your life. Understanding that difference, and learning to work with it, may be one of the next frontiers in medicine.
Notable Quotes
The squirrels had been inadvertent archivists, their digestive systems preserving a snapshot of entire ecosystems— Tyler Murchie, Hakai Institute biomolecular archaeologist
Understanding the genetic instructions that enable regeneration in other animals could eventually open pathways toward regenerative medicine in humans— Josh Currie, Wake Forest University biologist
The Hearth Conversation Another angle on the story
Why does ancient squirrel poop matter so much? It's just waste.
Because it's a time capsule. When a squirrel eats, it ingests DNA from everything around it—plants, insects, larger animals it scavenges. That DNA survives in the feces, frozen in permafrost for hundreds of thousands of years. It's like having a detailed receipt of what the entire ecosystem looked like.
And the regeneration research—if axolotls can regrow limbs, why can't we?
We could once, evolutionarily speaking. Somewhere along the way, mammals traded that ability for other advantages. But the genes are still there, dormant. If we can identify which genes the axolotl activates and we don't, we might be able to flip that switch back on.
That sounds like it could take decades.
It probably will. But the first step is knowing it's possible at all. For a long time, we assumed regeneration was just something we'd lost forever.
What about the mutations angle—that seems almost contradictory. Mutations sound dangerous.
They are, sometimes. Cancer is mutation. But mutation is also how we adapt, how we survive. The point is that we're not static. Your body at fifty is genetically different from your body at twenty, and scientists are learning to read those differences as information rather than just noise.
So the Asimov interview—why include that?
Because he was thinking about these questions fifty years ago. How do we live alongside intelligence we create? How do we explore beyond ourselves? The questions haven't changed. The technology has just caught up.