You’ve probably seen it with your own eyes before, but a research team that published its findings in the journal Science says it noticed it at an epigenetic level: big dogs age faster. Chihuahuas, for as obnoxiously yappy as they are, seemed to last forever, while Great Danes, those big lovable galoots, give you about a decade before they cross the rainbow bridge.
Researchers at Arizona State University analyzing DNA from nearly 900 dogs in the Dog Aging Project finally know why big dogs don’t last as long. It all has to do with rogue “jumping genes.”
Scientists Say ‘Jumping Genes’ Could Explain Why Big Dogs Have Shorter Lives
Inside dog DNA, a specific class of “jumping” genes called LINE1s exists. Normally, a biological process called DNA methylation stamps chemical tags onto these genes to keep them locked down, but as big dogs age, that regulatory process falls apart and LINE1s start shaking loose, jumping between chromosomes, shredding DNA apart in the process, thus causing instability in the cells, triggering inflammation and cancer.
This happens to all dogs, but in big dogs it happens catastrophically and early. Giant breeds shed roughly 35 percent more LINE1 methylation per year than smaller dogs that fit in a purse.
Or, to put it less scientifically: there’s just too much dog for their bodies to keep up with. Humans specifically bred big dogs for their rapid growth, but that early growth leads to a genetic mess later in life, as their biological clocks essentially run twice as fast as a smaller dog’s.
The researchers think these out-of-control jumping genes could be a universal mammalian aging mechanism, and that learning more about them could eventually help us learn a little about ourselves, too, since dogs get a lot of the same age-related diseases that we do, largely because we share environments.
A gynecologist points to the head of a fetus in an ultrasound image. | Jan Woitas/picture alliance via Getty Images
We live in an era of endless optimization. Fitness trackers help us measure our lifespan, people are consuming piles of protein in an attempt to be their best selves, and there’s even an urge to maximize our morality. In a world of constant self-improvement, it’s no wonder that journey has reached our attempts at reproduction.
Kristen V. Brown is a journalist and author of the forthcoming book The Immortal Womb: The Centuries-Long Quest to Control the Female Body and Hack Human Reproduction. As the title suggests, she writes about all of the ways people are trying to exert more control over the process of having children.
“I think that what we’re seeing right now is that people will do anything they can to have the healthiest baby possible,” she told Vox. “So much is out of your control, and people are just trying to figure out, how do I get more control? How do I skew the odds in my favor?” She says that one way people try to get more agency is through a technology called PGT-P, or preimplantation genetic testing for polygenic risk.
“If you go through IVF, very often they’ll have you do a basic genetic screening that can detect things like Down syndrome. This screening takes that up a notch,” Brown said. “It uses that same preimplantation genetic testing to look for the likelihood of complex genetic conditions — stuff like heart disease, like diabetes — in order to, quote, ‘let people have the healthiest baby.’”
But what can potential parents do with that knowledge? How far can this technology go? And what are the ethics of using it in the first place? We discuss that and more on the latest episode of Explain It to Me, Vox’s weekly call-in podcast.
Below is an excerpt of my conversation with Brown, edited for length and clarity. You can listen to the full episode on Apple Podcasts, Spotify, or wherever you get your podcasts. If you’d like to submit a question, send an email to askvox@vox.com or call 1-800-618-8545.
What other things are they testing embryos for?
For conditions that are only impacted by one gene, like Huntington’s disease, it’s very easy to say, ‘Does this embryo have it or not?’ with a pretty good degree of confidence. But that’s not how this technology works. Something like heart disease, for example, is impacted by hundreds of genes. Also, something like heart disease is not only genetic. It’s affected by environment and lifestyle.
I think that what’s motivating most people is the health aspect. But a lot of these companies are marketing these tests, saying they can also look for height. They can look at eye color. Some of them are promising IQ. How do you even define intelligence, let alone how do you define the genetics of intelligence? Alzheimer’s disease, longevity, which embryo is going to live the longest life. So it’s already gone beyond disease into some of these more aesthetic concerns.
Do we know how many people are doing this?
I think it’s a very small number of people at this point. But I think that we’re seeing more and more companies in the space, and we’re seeing more and more support from fertility doctors.
I want to emphasize that most mainstream medical societies are against this. Most of the IVF doctors I know do not think this has value. Most people in the genetic space do not think this technology has value either for embryos or for adults, but I think we’re seeing support growing.
I think that a lot of people in the fertility space are already envisioning a future where this does become more mainstream because the idea is just so appealing, even if the technology has flaws.
What about embryo editing? Is that something we’re seeing? Can people go in and change things around?
Not right now. Embryo editing is very much illegal in the United States. It is illegal in most countries. How can you be sure enough that it’s safe? Because you won’t know for sure until an embryo grows up into an adult whether anything went awry.
Right now it is illegal, but there is growing interest as the technology has gotten better. Most of the support right now for embryo editing is for disease. The argument for it is that, let’s say you are a carrier for Huntington’s disease or you have Huntington’s disease. Right now, there is something that you can do. You can use polygenic screening to select the embryos that don’t have the disease, but in IVF, even if you don’t have a terrible disease hiding in your DNA, it’s hard to get a lot of embryos.
You have these situations where couples have to do rounds and rounds and rounds of IVF to get one or two embryos that aren’t carriers for a harmful variant, right? And so the argument for it is, let’s give these people a better shot.
But I imagine there are people out there who aren’t looking into editing simply for making children more resistant to diseases. They are looking at those things like eye color and height.
There’s actually a name for that. This tech executive called Brian Armstrong coined this term, the Gattaca stack, [named] after the movie. The vision is to use a suite of fertility technologies to make the perfect human.
The first thing they want to use is this technology called in vitro gametogenesis, which is where you take a skin cell and you turn it into an egg and a sperm, and then you make an embryo with it, so women don’t have to go through rounds of IVF.
The idea is that you can get tons and tons and tons of embryos, and then you can use PGT-P to then screen for the best ones, and then you can use an artificial womb to incubate and grow them.
This brings to mind a certain E word, and that word is eugenics. What are the ethics here?
Because on one hand, I can understand that there are parents who are like, “I just want to have a healthy baby. I want to bring a child into this world. I just want to put my best foot forward with this human that I’m going to bring to Earth.” And then on the other hand, it gets a little weird.
It gets weird fast. In some ways, we’ve already gone down that slippery slope. Right now, even if you don’t go through IVF, we screen against Down syndrome early in pregnancy. Down syndrome is a condition in which you have a disability, but you can live a full, happy, healthy life. For a long time, parents of kids with Down syndrome have argued that already selecting and screening against Down syndrome pregnancies is a form of [eugenics].
As technology gets more advanced, we see that same question applied to more and more conditions. I think that one of the things that we don’t talk about enough is that the genome is complicated. You can’t actually just go in there and be like, ‘I want a tall baby with blue eyes and a great laugh.’
I think that becoming a parent is an exercise in giving up control, and that’s easier for some people than others. I have so much sympathy and empathy for people who are trying to stack the deck. But I think there are just so many variables when it comes to human reproduction that we are never going to be able to fully control the process, as much as we might want to and as appealing as that might sound.
Shark week has come and gone, but that doesn’t mean we can’t squeeze in a few more shark stories before the year is up.
According to a study published in Marine Biology and detailed by ScienceAlert, scientists analyzing thousands of drone flights off Australia’s east coast discovered that dozens of young scalloped hammerhead sharks are just chilling in the shallow waters right next to popular swimming beaches. The beachgoers are likely just a tiny bit more concerned about the hammerheads than the hammerheads are about the beachgoers.
While reviewing more than 20,000 drone flights for Queensland’s SharkSmart program, researcher Maddison Cross and her team spotted swarms of up to 100 juvenile hammerheads hanging out at tourist hot spots like Burleigh Beach and Noosa Main Beach. These are roughly three-and-a-half-foot-long teenagers.
Why Young Hammerhead Sharks Are Gathering Just off Popular Australian Beaches
The young aquatic predators cluster in shallow surf zones during Australia’s autumn months as scientists suspect that these coastal cluster hangout spots were kind of like a combination safe haven and food court for the sharks, allowing the juveniles to feed on prey that hang out at nearby reefs while offering protection via their safety-in-numbers approach.
Beachgoers are probably worried about shark attacks, but the sharks themselves were the ones in real danger, as these gathering spots overlap with Queensland’s shark control programs, which are often lethal. Shark nets and baited drum lines are responsible for killing over 600 scalloped hammerheads between 2000 and one in 2024; rather unfortunate considering that it’s a critically endangered species.
Sharks generally mind their own business and will scatter if a human comes near, as evidenced by the fact that paddleboarders and snorkelers occasionally pass through these hang-out clusters, causing the groups to temporarily break up before reforming once the coast is clear, but if you’re planning on a trip down under to take in some of Australia’s gorgeous beaches, just know that there might be hundreds and hundreds of adolescent hammerhead sharks floating just beneath your feet.
Over the past year or so, I’ve covered a lot of Neanderthal-related discoveries. The biggest takeaway from it all is that they weren’t too dissimilar from us, which is in itself a revelation given that for so long we made their very name synonymous with stupid and out of touch. A new study of Neanderthals published recently in Scientific Reports follows that trend of revealing the humanity of the Neanderthal, and it’s all thanks to a stabbing.
Researchers were looking at a 75,000-year-old partial skeleton nicknamed Shanidar A, named after where they found it, the Shanidar Cave in Iraq. It had a circular 15-millimeter puncture on the left shoulder blade. Speaking to Reuters, study lead author Dr. Emma Pomeroy of the University of Cambridge says that the fatal wound was likely caused by a downward thrust from a wooden spear that punched through the chest, into the lung, and through the heart before exiting the back.
Rough stuff. One could even call it distinctly Neanderthal behavior, assuming it was the result of some kind of clash among rivals, even though it could’ve just as easily been an accident.
This Neanderthal May Have Been Killed by a Spear. His Other Injuries Tell a Different Story.
The suggestion of a violent act also reveals a distinctly human, maybe even kind of touching reality upon closer examination: this Neanderthal experienced a degree of empathy. Not in the stabbing that punctured lungs and heart, but in other features. Shanidar A had severe but healed facial trauma that included a mouth of mangled teeth, an injury that the researchers theorize Shanidar A could’ve only survived with communal help since they probably couldn’t properly chew their food.
As Pomeroy said, “The pain would have been extreme, and basic needs like eating and drinking would have been difficult, perhaps meaning Shanidar A needed food mashing and being able to rest. It’s likely that Shanidar A did need some care from members of the group for some basic needs during recovery.”
Neanderthals had some real bad PR, but the more we find out about them, the more we realize they weren’t a bunch of stupid brutes that forgot to branch off into higher intelligence like the rest of us. They were violent, but they were also caring, and they knew how to keep their communities alive and thriving, even if, in time, Homo sapiens came out on top.
On Friday, a new exhibit at the American Museum of Natural History in New York City opened: Monarch's Journey, featuring the work of cartoonist Peter Kuper.
From a museum statement:
"Wrapping the walls near the Museum's extensive butterfly research collection in the Richard Gilder Center for Science, Education, and Innovation, the exhibit explores the challenges monarchs face on their 3,000-mile flight through Kuper's bold illustrations, accompanied by a video installation of monarchs in motion.
Login
