Learn about the impressive memories of goldfish. Plus, hear from Dr. Kat Arney about why an evolutionary perspective may be the key to fighting cancer.
Learn about the impressive memories of goldfish. Plus, hear from Dr. Kat Arney about why an evolutionary perspective may be the key to fighting cancer.
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Goldfish Have Great Memories, Thank You Very Much by Anna Todd
Additional resources from Dr. Kat Arney:
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/how-cancer-evolves-in-the-body-w-dr-kat-arney
[MUSIC PLAYING] ASHLEY HAMER: Hi, you're about to get smarter in just a few minutes with Curiosity Daily from Curiosity.com. I'm Ashley Hamer.
NATALIA REAGAN: And I'm Natalia Reagan. Today, you'll learn about the impressive memories of goldfish. You'll also hear from Dr. Kat Arney about why a new evolutionary perspective of cancer may be the key to effectively fighting it.
ASHLEY HAMER: Let's satisfy some curiosity.
NATALIA REAGAN: Goldfish, not just for snacks. If you've ever said a forgetful person had the memory of a goldfish, listen up. Mounting evidence suggests that goldfish actually have a pretty good memory. Seriously, forget that three-second memory myth you've heard. Studies on fish similar to goldfish have shown that they can remember things for a year or more. So if you owe a goldfish some money, you better pay up, or you might be sleeping with the fishes.
For one study, behavioral ecologist Culum Brown taught some rainbow fish to escape an artificial trawl net with a hole in it. When the fish were tested again a year later, they remembered exactly where the escape route was. I'm impressed. And when it comes to goldfish specifically, no long-term studies have tested their memories over the years. But there is evidence that they can remember things for a month or more. In fact, they can even be trained, and they'll remember those tricks for months.
For example, in one study, researchers successfully taught some goldfish to press a lever to get food. That's cool on its own, right? But it gets better. Over the next three months, the researchers gradually shortened the amount of time the lever would release food until it was down to just an hour a day. The goldfish stopped pressing the lever at any other time and swarmed the lever right before the feeding hour. That suggests that they learned and remembered exactly when the lever would work.
Goldfish and their close relatives have also been shown to recognize their owners, play fetch, distinguish classical music from blues music, and even play soccer. Now I'm really impressed. Fish are a lot more complicated than you think. That's why experts recommend that goldfish owners regularly switch up the tank environment both to alleviate boredom and extend their pets' lives. Of course, you could always try teaching Goldie some new tricks because there's actually fish training kits you can buy online. It's not quite the same as having a dog, but hey, it'll keep life interesting for your finned friend.
ASHLEY HAMER: 50 years ago, many people thought that we'd have a cure for cancer within a decade. Obviously, that didn't happen. Cancer has proven to be way more complex than we thought, and fighting against it has required some new ways of thinking.
Our guest today says that to truly gain control over cancer, we need to see it not as human cells gone wrong but as rebel cells that are adapting and evolving within their environment, just like any organism would. Dr. Kat Arney is a UK-based science writer and broadcaster and author of the new book Rebel Cell-- Cancer, Evolution, and the New Science of Life's Oldest Betrayal. In our conversation, I asked her why she thinks the classic definition of cancer is totally wrong.
KAT ARNEY: So that's the phrase that I always used to write when I was at Cancer Research UK. I'd have to do all the stuff for the website, like, what is cancer? And we'd always sit down and start with this sentence-- "Cancer starts when a cell picks up mutations--" so you have changes in its genetic code and its DNA-- "and it multiplies out of control."
And the more I started researching for this book-- I was expecting to write a book that looks at that, and it goes, well, you pick up this mutation and that mutation, this mutation, and that's your cancer. And then, this is how we treat it by tackling all these, the products of these aberrant genetic changes, which is where a lot of cancer treatment is going now.
But then I started to learn about really what is going on at the level of all these changes because we're so fixated as scientists on, what are the mutations in the cancer? So what has happened to these cells to make them go wrong? And we never really stop to think about, well, what's going on in normal tissue?
And so a couple of years ago, there were some researchers at the Sanger Institute just outside Cambridge in the UK, and they did this really mind-blowing experiments that they can only do it now that we have the DNA sequencing technology where you can look at tiny, tiny, tiny clusters of cells and look at all the DNA and all the changes in there. And so these techniques have previously just been applied to tumors. It's like, if you're going to study cancer, you want to study cancers, right? Makes sense. But they were like, well, has anyone really looked at normal tissue?
And so they got hold of normal healthy tissue-- from skin; from the esophagus-- that's the tube that connects your mouth to your stomach; from the endometrium, the lining of the womb. And this is from healthy people of a range of ages, from young to elderly. Healthy tissue, no signs of cancer. And they looked at these completely normal cells and discovered that healthy tissue is an absolute patchwork of mutation. So by the time you get to middle age and certainly by the time you're in your sixth or seventh decade, your skin is just a patchwork of mutation and not only that.
If we found these mutations in a cancer, we would say that is the cancer gene that is driving that cancer. And so this is like, hang on. If we're starting with this definition that cancer is what happens when a cell picks up mutations and goes out of control, but you're saying that most of our normal tissue is full of what we would think of as cancer mutations, then there's much more to cancer than just mutations.
And so that's what I start to explore in the book in a lot more detail, this idea of the tissue environment, of the ecology of the body, of the idea that cancer is made up of lots and lots of little pockets of quite genetically different cells that are all doing their own kind of evolutionary "choose your own adventure."
They're almost like species-- members of species evolving in the ecology of the tissue in which they find themselves. And that tissue ecology changes depending on where in the body it is, and it changes throughout our lifetime as well. And that is a new way of thinking about how does cancer start, how does it emerge, how does it evolve in the body, how does it evolve resistance to therapy, and then what can we do more effectively to prevent and treat it?
You get this idea that cancer is just a modern disease, and it's just a human disease, and we brought it on ourselves with our terrible, toxic modern lifestyles. But actually, you start to look back through history, and cancer is found across the tree of life, pretty much every-- certainly every animal species with the exception of, weirdly, jellyfish and some types of sponges. Pretty much all other animals have examples of cancer. This is a deep, deep phenomenon throughout evolutionary time.
There is evidence of fossils. There's a fossilized turtle from 240 million years ago with a tumor in it. So it's like, this is a deep and ancient disease. And it emerges out of multicellular life. And sort of where the idea of ecology and evolution of the species of cancer cells in you-- it's not that-- they start from human cells. A cancer that emerges in a human starts from human tissue, but the changes that happen to it are really extreme.
We define species as how different species are. We define them by their DNA. Like, do they have different numbers of chromosomes from each other, one species compared to another? Do they have significant genetic changes? Comparing humans to chimpanzees, 99% of our DNA is the same. Our chromosomes are very similar, except chimpanzees have 24 pairs, and we have 23 pairs.
When you look at cancer cells, when you see how messed up and how different they are and that one cluster in one part of a tumor may be different from another cluster and another part of the same tumor and very different from a secondary cancer that's found somewhere else in the body that are spread there, these are really different. And if you found two animal species that were this chromosomally different, you'd say they were different species.
So this is just-- it's a metaphor, but it's an interesting biological question about the rate of evolution and the way that these different types of cells are trying to survive. It really is like survival of the fittest. It's evolution by natural selection going on in a microcosm. I call it the dumpster fire of evolution that's going on in the body.
ASHLEY HAMER: Dr. Kat Arney is a UK-based science writer and broadcaster and author of the new book Rebel Cell-- Cancer, Evolution, and the New Science of Life's Oldest Betrayal. She's also the host of the Genetics Unzipped podcast. And she'll be back tomorrow to talk about all the weird things that cancer can do. You can find links to all of that and more in today's show notes.
NATALIA REAGAN: Oh, that was fascinating.
ASHLEY HAMER: I kept thinking that while I was talking to her how fascinating this is and how cool it is, but it's also, like, evil. [CHUCKLES]
NATALIA REAGAN: Yeah.
ASHLEY HAMER: I mean, it's cancer. It kills so many of our loved ones. It's awful, but you need to know your enemy at the same time.
NATALIA REAGAN: So let's recap today's takeaways.
ASHLEY HAMER: Well, we learned that goldfish may not be members of Mensa, but they do have pretty impressive memories. They can recognize their owners and distinguish between different types of music, and, plus, they can play fetch. Who needs a dog when you can scale down with a super smart goldfish? This segment inspired me to watch tons of YouTube videos of goldfish doing tricks. And it's so entertaining.
NATALIA REAGAN: Did you see comet? They were a goldfish who could do all sorts of tricks, including doing the limbo. They could play soccer. They could slalom between little goldfish cones. [LAUGHS]
ASHLEY HAMER: [CHUCKLES]
NATALIA REAGAN: I feel like the Twitter fish versus bird people, this is a story that they can get into.
ASHLEY HAMER: Yes.
NATALIA REAGAN: We can really "school" them on the subject.
ASHLEY HAMER: Aha.
NATALIA REAGAN: Oh.
ASHLEY HAMER: There it is. [LAUGHS]
NATALIA REAGAN: God, it's really awful, I know. We should just say, "fin." [CHUCKLES]
ASHLEY HAMER: They're chummy pets.
NATALIA REAGAN: Ah! (CHORTLING) Hey-hey-hey.
ASHLEY HAMER: That's all I got. [LAUGHS]
NATALIA REAGAN: That's real good.
ASHLEY HAMER: I'm learning.
NATALIA REAGAN: We also learned that cancers are more like their own species rather than a nonliving entity invading our bodies. Even tumors can have different types of DNA within the same tumor. These findings can hopefully inform scientists on how they can better treat certain cancers and, hopefully, like we hope would happen 50 years ago, actually find a cure.
ASHLEY HAMER: Yes, and definitely check out the second segment of this interview tomorrow because Kat Arney just blew my freaking mind. She's like, I'm going to blow your mind. And then she said the thing, and I was like, oh my god, my mind is blown. It happens. You'll hear it. The whole thing happens.
NATALIA REAGAN: It's really cool.
ASHLEY HAMER: Who knew that cancer was so interesting? I mean, you just think of it as this terrible affliction, and it is. The fact that it can take us down as well as it can is because it's so good at its job, and that's something to respect.
NATALIA REAGAN: Today's stories were written by Ashley Hamer and Anna Todd and edited by Ashley Hamer, who's the managing editor for Curiosity Daily.
ASHLEY HAMER: Scriptwriting was by Natalia Reagan and Sonja Hodgen. Today's episode was edited by Natalia Reagan. And our producer is Cody Gough.
NATALIA REAGAN: Join us again tomorrow to learn something new in just a few minutes.
ASHLEY HAMER: And until then, stay curious.
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