Orange Cat Lovers, Rise Up!

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 https://www.cell.com/current-biology/fulltext/S0960-9822(25)00391-4 this week. Have a question about the animals all around us? Email us at [email protected] mailto:[email protected] — we'd love to hear from you! Listen to Short Wave on Spotify https://n.pr/3HOQKeK and Apple Podcasts https://n.pr/3WA9vqh. See pcm.adswizz.com https://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 https://www.npr.org/about-npr/179878450/privacy-policy

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

  This message comes from NPR sponsor, Viori, featuring the Sunday Performance Jogger. Receive 20% off your first purchase at viori.com/npr on any US orders over $75 and free returns. Exclusions apply. Visit the website for full terms and conditions.

• 0:19Emily Kwong?

  You're listening to Short Wave from NPR.

• 0:24Emily Kwong?

  Hey, Short Wavers. Regina Barber here.

• 0:26Speaker 02

  And Emily Kwong.

• 0:27Emily Kwong?

  With our biweekly science news roundup, featuring the host of All Things Considered, Juana Summers.

• 0:32Speaker 02

  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.

• 0:39Emily Kwong?

  Yes, we're going to talk about orange cats. Also, a tech prototype for your bike that could help map safer routes.

• 0:45Speaker 02

  And the connection between gum disease and heart problems.

• 0:48Emily Kwong?

  All that on this episode of Short Wave, the science podcast from NPR.

• 1:07Speaker 03

  Stay tuned for the following announcements and messages from our sponsors. This message comes from Doppel. Doppel is the agentic social engineering defense platform, fighting back against impersonation and manipulation. As attackers use AI to make their tactics more sophisticated, Doppel uses it to fight back, automatically dismantling cross-channel attacks, building team resilience, and providing agentic email protection. Doppel, dedicated to outpacing what's next in social engineering. Learn more at doppel.com. That's D-O-P-P-E-L dot com.

• 1:41Speaker 00

  This message comes from BetterHelp. Your brain has limited storage, so why is it still holding on to that embarrassing moment from years ago? BetterHelp is an online therapy platform that gives you space to talk about what's taking up too much of yours. BetterHelp is now in-network with more than 125 health plans, with many copays as low as $15 for eligible members. And if you don't have eligible insurance, you can still get 20% off your first month. Visit betterhelp.com/npr. Cost and coverage may vary. Discount cannot be combined with insurance.

• 2:16Speaker 03

  This message comes from Capella University. That spark you feel? That's your drive for more. Capella University's FlexPath learning format lets you earn your degree at your pace without putting life on pause. Learn more at capella.edu.

• 2:31Regina Barber?

  All right, Wanda, where do you want to begin? I have a guess.

• 2:34Emily Kwong?

  I mean, there's no other place but orange cats.

• 2:36Regina Barber?

  Right, totally.

• 2:37Emily Kwong?

  Yeah, the greatest cats of all time. That is a fact. According to my orange tabby, Zuko.

• 2:45Regina Barber?

  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.

• 2:53Emily Kwong?

  Guys, I have to tell you something. I also have an orange cat, and guess what? Also a boy. OK, this is perfect because approximately 80% of orange cats are males, and it's something researchers and cat enthusiasts have long noticed. 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.

• 3:18Regina Barber?

  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.

• 3:36Emily Kwong?

  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 Kaelin at Stanford University. Both papers were published in the journal Current Biology this week.

• 4:04Regina Barber?

  So no orange cats were harmed in the pursuit of this genetic mystery.

• 4:07Emily Kwong?

  Well, that's good.

• 4:09Regina Barber?

  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.

• 4:18Speaker 05

  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.

• 4:31Speaker 02

  Interesting, but what about other orange animals like tigers or orangutans? Are their orange colors linked to their sex chromosomes too?

• 4:38Regina Barber?

  So actually, no, their orange color arises from regular chromosomes known as autosomes.

• 4:44Speaker 02

  Proving what we always knew, orange cats really are that special.

• 4:47Regina Barber?

  And in case you were wondering, all orange cats do share the same mutation, meaning, Wana, there was a first orange cat.

• 4:54Speaker 02

  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?

• 5:05Regina Barber?

  Yes, Wana. 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.

• 5:22Emily Kwong?

  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.

• 5:43Speaker 02

  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?

• 5:51Emily Kwong?

  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 matched 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.

• 6:10Regina Barber?

  And that might seem like an obvious connection to make, but the lead researcher, Joe Breda, 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 like gauging how safe routes were. And that's where the sensor could help. Like, he just wants to encourage more people to bike.

• 6:27Speaker 06

  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?

• 6:35Speaker 02

  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?

• 6:42Emily Kwong?

  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.

• 6:53Regina Barber?

  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 crowdsourced data from the sensors can feed into a map that helps like find safer bike routes.

• 7:09Speaker 02

  I mean, that does sound pretty incredible.

• 7:11Regina Barber?

  Agreed.

• 7:11Speaker 02

  The power of science. Indeed. All right, last story of the day. There is a connection between gum disease and heart health?

• 7:18Emily Kwong?

  Yes, so people with gum disease could 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.

• 7:35Speaker 02

  I watch too many medical shows, so I know this one. That's AFib, right? Like in a regular rapid heart rhythm?

• 7:39Emily Kwong?

  Right. AFib is common, affecting about 10 million US 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 US adults.

• 7:53Speaker 02

  I did not know that. So tell us, how are they connected?

• 7:56Emily Kwong?

  Well, this topic was of special interest to one of the study authors, Shunsuke Miyaochi. He's a cardiologist at Hiroshima University in Japan. Both his parents happen to be dentists. So even though Shunsuke works with hearts, he said he's always paid attention to people's oral care.

• 8:11Regina Barber?

  To study the connection, his team infected mice with the bacteria associated with gum disease and found that these mice developed AFib more easily than those without the bacteria. They also saw that mouth bacteria migrated to the heart, like in mice and in humans.

• 8:26Emily Kwong?

  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.

• 8:35Regina Barber?

  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.

• 8:44Speaker 02

  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?

• 8:52Regina Barber?

  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.

• 9:16Emily Kwong?

  Everyone we spoke to hopes this study encourages greater collaboration between dentistry and medicine to keep people's gums and hearts healthy.

• 9:25Speaker 02

  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.

• 9:29Regina Barber?

  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.

• 9:37Emily Kwong?

  Yeah, we should get all our orange cats together. Cat party.

• 9:39Regina Barber?

  Yeah.

• 9:41Emily Kwong?

  Thanks so much, Wana.

• 9:42Regina Barber?

  Thanks.

• 9:46Regina Barber?

  You can hear more of Wana on Consider This, NPR's afternoon podcast about what the news means for you.

• 9:53Regina Barber?

  This episode was produced by Elena Burnett and Rachel Carlson. It was edited by Rebecca Ramirez and Christopher Intagliata.

• 10:00Emily Kwong?

  Tyler Jones checked the facts. Kwesi Lee and Ted Mebane were the audio engineers. I'm Emily Kwong.

• 10:05Regina Barber?

  And I'm Regina Barber. Thank you for listening to Short Wave, the science podcast from NPR.

• 10:27Speaker 03

  Stay tuned for the following announcements and messages from our sponsors.