Short Wave - Orange Cat Lovers, Rise Up!

Episode Date: May 16, 2025

Approximately 80% of orange cats are males, including the four orange cats owned by the Short Wave team. Scientists have long suspected that orange color was a sex-linked trait — hiding somewhere on the X chromosome. Now, scientists at Stanford University and Kyushu University in Japan have characterized the mutation responsible for orange cat coloration. Both groups published their results in the journal Cell Biology this week. Have a question about the animals all around us? Email us at [e-mail] — we'd love to hear from you!Listen to Short Wave on Spotify and Apple Podcasts.See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, Shortwaivers, Regina Barbara here and Emily Kwong with our biweekly science news roundup featuring the host of all things considered Juana Summers. Hi, so I am excited to be here because I've heard we've got a whole range today, starting with a story about all of our beloved orange cats. Yes, we're going to talk about orange cats. Also, a tech prototype for your bike that could help map safer routes. And the connection between gum disease and heart problems. All that on this episode of Shortwave. The Science Podcast from NPR. All right, Juana, where do you want to begin?

I have a guess. I mean, there's no other place but orange cats. Right. Totally. Yeah, the greatest cats of all time. That is a fact. According to my orange tabby, Zuko, my blonde orange boy, Benny, also agrees. Maybe not the other three cats.

But our boss also has two orange cats, Tang and Dorito. Both of them are males, too. Guys, I have to tell you something. I also have an orange cat. And guess what? Also a boy. Okay, this is perfect. because approximately 80% of orange cats are males, and it's something researchers and cat enthusiasts have long notice.

Scientists suspected the reason may be that orange color is a sex-linked trait, meaning the mutation responsible for that ginger hue is found on their sex chromosomes, specifically their X chromosome. Male cats, just like male humans, have an X and Y chromosome. So any male cat with this mutation ends up orange. Female cats need the mutation on both of their X chromosomes to be fully orange, which is, statistically less likely. So nearly all calico and tortoiseshell cats are female because this mutation is found on only one of their X chromosomes. Interesting. So were they right? Was the mutation on the X chromosome? Yes. They found the mutation. They found its location. It's a single deletion on the X chromosome, which causes a nearby gene to be expressed in pigment cells, so cat hair color. This mutation was

independently located by two teams of scientists, one led by Hiro Sasaki in Japan and another by Chris Kaylin at Stanford University, both papers were published in the journal Current Biology this week. So no orange cats were harmed in the pursuit of this genetic mystery. Well, that's good. In fact, study author Greg Barsh says that the Stanford team partnered with cat lovers and community scientists to gather DNA samples from dozens of different orange cats. It's an example, I think, of how scientists and the public can work together to not

only uncover cool things, but also learn important aspects about biology. Interesting, but what about other orange animals like tigers or orangutans? Are their orange colors linked to their sex chromosomes too? So actually, no, their orange color arises from regular chromosomes known as autosomes. Proving what we always knew. Orange cats really are that special. And in case you were wondering, all orange cats do share the same mutation, meaning Juana, there was a first orange cat. Love that. All right. Let's move on to the next one and talk about sensors on bikes. I know standard bikes do not have them, but scientists are making these to help those of us that bike not get hit by cars. Yes, Juana. I just bought a bike. I just started biking. I don't want to get hit by a car.

So I was very interested in the study where like computer scientists created a system called proxy cycle. It's a sensor to monitor how close cars get to cyclists. The scientists deployed the sensor on 15 bikes over the span of two months in Seattle, Washington. So this bike sensor, costs less than $25 to make. It attaches to the left handlebar. And in this study, these 15 cyclists took 240 rides with the sensor and recorded over 2,000 close passes, though thankfully no collisions. And the researchers presented these findings at the conference on human factors in computing systems in Japan. Okay, so other than terrifying these bike riders, and to be clear, this sounds absolutely terrifying. What did these cars zooming too close to the riders tell researchers?

Interestingly enough, Seattle has collected bike collision data for the last 20 years. And this study compared five years of that data to the research team's two months of close passes. And the data sets match pretty well. This tells us that close passes, so when a car comes close to a bike, that might be a good indicator of your chances of an actual collision in that section of the road. And that might seem like an obvious connection to make. But the lead researcher Joe Brata at the University of Washington has surveyed cyclists and found that people who were like new to city biking weren't all that good at. gauging how safe routes were. And that's where the sensor could help.

Like, he just wants to encourage more people to bike. Can we lower the barrier of entry to cycling by creating a map of where is it safe or unsafe to bike before any accidents actually happen? Okay, right, that map. You said the sensor might be helpful in mapping safer bike routes, which would be super helpful. But how would it work? Joe says the next step is to deploy these sensors in more cities on more bikes. He also wants this to be accessible to as many people as possible, perhaps by making the software and design eventually open source.

And you know, Wana, we've gotten so used to, like, maps when we're driving, like, people's devices telling companies like Google where traffic is, allowing them to reroute themselves. Imagine something like that for cyclists where all of this, like, crowdsource data from the sensors can feed into a map that helps, like, find safer bike routes. I mean, that does sound pretty incredible. I agree. The power of science. Indeed.

All right. Last story of the day. There is a connection between gum disease and heart health? Yes. So people with gum disease could have. have a higher risk of heart failure or stroke, which we've known, but a recent study in the journal circulation offers even more insight on the gum disease heart connection and specifically the link between gum disease and atrial fibrillation. I watched too many medical shows, so I know this one.

That's AFIB, right? Like in a regular rapid heart rhythm. Right. Aphib is common. Affecting about 10 million U.S. adults, and now AFIB isn't necessarily life-threatening, but it can be dangerous, especially for older people. And gum disease is also really common. It affects nearly half of U.S. adults. I did not know that. So tell us, how are they connected? Well, this topic was a special interest to one of the study authors, Shunke Miyachi. He's a cardiologist at Hiroshima University in Japan. Both his parents happen to be dentists. So even though Shunke works with hearts, he said he's always paid attention to people's oral care. To study the connection, his team infected mice with the bacteria associated with gum disease and found that these

mice developed AFIP more easily than those without the bacteria. They also saw that mouth bacteria migrated to the heart, like in mice and in humans. Though David Wu at the Harvard School of Dental Medicine, who wasn't involved with the study, says the way the mice were infected with the bacteria could have made it easier to spread through the bloodstream. Still, like once the bacteria reaches the heart, the study authors think it may lead to tissue scarring or inflammation, which may contribute to all sorts of other problems like AFIP. That's really interesting. So I wonder, Does this just mean we should all be taking extra special care of our teeth, brushing more, brushing better? Yes. Yes. Elizabeth Jackson is a cardiologist at University of Alabama at Birmingham.

And she was not involved in the study, but she said it highlights the importance of, like, good dental care and like healthy living overall, like exercise, healthy food. We know that all the things that help reduce inflammation are good for the heart. and they clearly are good for other parts of us. Everyone we spoke to hopes this study encourages greater collaboration between dentistry and medicine to keep people's gums and hearts healthy. My dentist will be glad to know that I am sitting here with all of you and maybe I will go brush my teeth after this. I mean, I am actually going to do that. Wana, thank you so much for coming on the show and talking about orange cats with us. That was my favorite.

Yeah, we should get all our orange cats together. Cat party. Yeah. Thanks so much. want to. Thanks. You can hear more of Wana on Consider This NPR's Afternoon podcast about what the news means for you. This episode was produced by Elena Burnett and Rachel Carlson. It was edited by Rebecca Ramirez and Christopher and Taliatta.

Tyler Jones checked the facts. Cui Cui Lee and Ted Mebane were the audio engineers. I'm Emily Kwong. And I'm Regina Barber. Thank you for listening to Shortwave, the science podcast from NPR.