Science
Sea urchins made to order: Scripps scientists make transgenic breakthrough
Consider the sea urchin. Specifically, the painted urchin: Lytechinus pictus, a prickly Ping-Pong ball from the eastern Pacific Ocean.
The species is a smaller and shorter-spined cousin of the purple urchins devouring kelp forests. They produce massive numbers of sperm and eggs that fertilize outside of their bodies, allowing scientists to watch the process of urchin creation up close and at scale. One generation gives rise to the next in four to six months. They share more genetic material with humans than fruit flies do and can’t fly away — in short, an ideal lab animal for the developmental biologist.
Scientists have been using sea urchins to study cell development for roughly 150 years. Despite urchins’ status as super reproducers, practical concerns often compel scientists to focus their work on more easily accessible animals: mice, fruit flies, worms.
Scientists working with mice, for example, can order animals online with the specific genetic properties they are hoping to study — transgenic animals, whose genes have been artificially tinkered with to express or repress certain traits.
Researchers working with urchins typically have to spend part of their year collecting them from the ocean.
“Can you imagine if mouse researchers were setting a mousetrap every night, and whatever it is they caught is what they studied?” said Amro Hamdoun, a professor at UC San Diego’s Scripps Institution of Oceanography.
UC San Diego professor Amro Hamdoun holds a painted urchin. His breakthrough creating the creatures could lead to developments in science and medicine.
(Sandy Huffaker / For The Times)
Marine invertebrates represent about 40% of the animal world’s biological diversity yet appear in a scant fraction of a percentage of animal-based studies. What if researchers could access sea urchins as easily as mice? What if it were possible to make and raise lines of transgenic urchins?
How much more could we learn about how life works?
“You know how during the pandemic, everyone was making sourdough? I’m not good at making sourdough,” Hamdoun said recently at his office in Scripps’ Hubbs Hall. He set his sights instead on a project of a different sort: a new transgenic lab animal, “a fruit fly from the sea.”
In March, Hamdoun’s lab published a paper on the bioRxiv preprint server demonstrating the successful insertion of a piece of foreign DNA — specifically, a fluorescent protein from a jellyfish — into the genome of a painted urchin that passed the change down to its offspring.
The result is the first transgenic sea urchin, one that happens to glow like a Christmas bulb under a fluorescent light. (The paper has been submitted for peer review.)
The animals are the first transgenic echinoderms, the phylum that includes starfish, sea cucumbers and other marine animals. Hamdoun’s mission is to make genetically modified urchins available to researchers anywhere, not just those who happen to work in research facilities at the edge of the Pacific Ocean.
Postdoctoral researcher Elliot Jackson works with sea urchin eggs in a lab at Scripps.
(Sandy Huffaker / For The Times)
“If you look at some of the other model organisms, like Drosophila [fruit flies], zebrafish and mouse, there are well-established resource centers,” said Elliot Jackson, a postdoctoral researcher at Scripps and lead author of the paper. “If you want a transgenic line that labels the nervous system, you could probably get that. You could order it. And that’s what we hope we can be for sea urchins.”
Being able to genetically modify an animal supercharges what scientists can learn from it, with implications far beyond any individual species.
“It will transform sea urchins as a model for understanding neurobiology, for understanding developmental biology, for understanding toxicology,” said Christopher Lowe, a Stanford professor of biology who was not involved in the research.
The lab’s breakthrough, and its focus on making the animals freely available to fellow scientists, will “allow us to explore how evolution has solved a lot of really complicated life problems,” he said.
Researchers tend to study mice, flies and the like not because the animals’ biology is best suited to answer their questions but because “all the tools that were necessary to get at your questions were built up in just a few species,” said Deirdre Lyons, an associate professor of biology at Scripps who worked with Hamdoun on early research related to the project.
Expanding the range of animals available for sophisticated lab work is like adding colors to an artist’s palette, Lyons said: “Now you can go get the color that you really want, that best fits your vision, rather than being stuck with a few models.”
Painted urchins and humans live vastly different lives but genetically are quite similar.
(Sandy Huffaker / For The Times)
On the ground floor of Hamdoun’s office building is the Hubbs Hall experimental aquarium, a garage-like space crammed with tanks full of recirculating seawater and a motley assortment of marine life.
On a recent visit, Hamdoun reached into a tank and gently dislodged a painted urchin. It scooched with surprising speed across an outstretched palm, as if exploring alien terrain.
The last common ancestor of L. pictus and Homo sapiens lived at least 550 million years ago. Despite the different evolutionary paths we’ve since traveled, our genomes reveal a shared biological heritage.
The genetic instructions that drive the transformation of a single zygote into a living body are strikingly similar in our two species. Specialized systems differentiating from a single fertilized egg and the translation of a jumble of proteins into a singular living thing — on the cellular level, all of that proceeds in much the same way for urchins and people.
These animals are “really fundamental to our understanding of all of life,” Hamdoun said, placing the urchin back in its tank. “And historically, very inaccessible genetically.”
The experimental aquarium was built in the 1970s, when scooping life from the sea was the only way to acquire research specimens. A few floors up in Hubbs Hall, Hamdoun led the way into the urchin nursery — the first large-scale effort to raise successive generations of the animals in a laboratory. At any given moment, the team has 1,000 to 2,000 sea urchins in various stages of development.
Hamdoun points to transgenic sea urchins his lab is raising at Scripps.
(Sandy Huffaker / For The Times)
Row upon row of tiny plastic tanks stood against a wall, each containing a lentil-size juvenile urchin. A strip of tape on each tank noted the animal’s genetic modification and date of fertilization. On some, a second bit of tape indicated animals that had the modification in their sex cells’ DNA, meaning it could be passed down to offspring. (For this reason, the lab keeps its urchins scrupulously separate from the wild population.)
“One of the big questions in all of biology is to understand how the series of instructions in the genome gives you whatever phenotype you want to study,” Hamdoun said — essentially, how the string of amino acids that is an animal’s genetic code gives rise to the characteristics of the living, respiring creature. “One of the fundamental things you have to do is be able to modify that genome, and then study what the outcome is.”
He pointed to a tank containing a tiny urchin from whose genetic code the protein ABCD1 has been snipped.
ABCD1 acts like a bouncer, Hamdoun explained, parking along the cell membrane and ejecting foreign molecules. The protein’s action can preserve the cell from harmful substances but can sometimes work against an organism’s best interest, as when it prevents the cell from absorbing a necessary medication.
Researchers using urchins in which that protein no longer works can study the movement of a molecule through an organism — DDT, for example — and measure how much of the substance ends up in the cell without the confounding interference of ABCD1. They can reverse-engineer how big a role ABCD1 plays in preventing a cell from absorbing a drug.
One biology professor said Scripps’ work will transform sea urchins as a model for research.
(Sandy Huffaker / For The Times)
And then there are the fluorescent urchins.
“The magic happens in this room,” Jackson said, walking into a narrow office with $1 million worth of microscopes at one end and a decades-old hand-cranked centrifuge bolted to a table at another.
He placed a petri dish containing three pencil-eraser-size transgenic urchins under a microscope. At 120 times its size, each looked like the Times Square New Year’s Eve ball come to life — a glowing, wiggling creature of pentamerous radial symmetry.
Fluorescence is not just an echinoderm party trick. Lighting up the cells makes it easier for researchers to track their movement in a developing organism. Researchers can watch as the early cells of a blastula divide and reorganize into neural or cardiac tissue. Eventually, scientists will be able to turn off individual genes and see how that affects development. It will help us understand how our own species develops, and why that development doesn’t always proceed according to plan.
The lab has “done a great job. It’s really been welcomed by the community,” said Marko Horb, senior scientist and director of the National Xenopus Resource at the University of Chicago’s Marine Biological Laboratory.
Horb runs the national clearinghouse for genetically modified species of Xenopus, a clawed frog used in lab research. Funded in part by the National Institutes of Health, the center develops lines of transgenic frogs for scientific use and distributes them to researchers.
Hamdoun envisions a similar resource center for his lab’s urchins. They’ve already started sending tiny vials of transgenic urchin sperm to interested scientists, who can grow bespoke urchins with eggs acquired from Hamdoun’s lab or another source.
Hamdoun vividly recalls the time he spent earlier in his career trying to track down random snippets of DNA necessary for his research, the disappointment and frustration of writing to professors and former postdocs only to find that the material had long been lost. He’d rather future generations of scientists spend their time on discovery.
“Biology is really interesting,” he said. “The more people can get access to it, the more we’re going to learn.”
Three transgenic sea urchins in a petri dish.
(Sandy Huffaker / For The Times)
Science
Commentary: My toothache led to a painful discovery: The dental care system is full of cavities as you age
I had a nagging toothache recently, and it led to an even more painful revelation.
If you X-rayed the state of oral health care in the United States, particularly for people 65 and older, the picture would be full of cavities.
“It’s probably worse than you can even imagine,” said Elizabeth Mertz, a UC San Francisco professor and Healthforce Center researcher who studies barriers to dental care for seniors.
Mertz once referred to the snaggletoothed, gap-filled oral health care system — which isn’t really a system at all — as “a mess.”
But let me get back to my toothache, while I reach for some painkiller. It had been bothering me for a couple of weeks, so I went to see my dentist, hoping for the best and preparing for the worst, having had two extractions in less than two years.
Let’s make it a trifecta.
My dentist said a molar needed to be yanked because of a cellular breakdown called resorption, and a periodontist in his office recommended a bone graft and probably an implant. The whole process would take several months and cost roughly the price of a swell vacation.
I’m lucky to have a great dentist and dental coverage through my employer, but as anyone with a private plan knows, dental insurance can barely be called insurance. It’s fine for cleanings and basic preventive routines. But for more complicated and expensive procedures — which multiply as you age — you can be on the hook for half the cost, if you’re covered at all, with annual payout caps in the $1,500 range.
“The No. 1 reason for delayed dental care,” said Mertz, “is out-of-pocket costs.”
So I wondered if cost-wise, it would be better to dump my medical and dental coverage and switch to a Medicare plan that costs extra — Medicare Advantage — but includes dental care options. Almost in unison, my two dentists advised against that because Medicare supplemental plans can be so limited.
Sorting it all out can be confusing and time-consuming, and nobody warns you in advance that aging itself is a job, the benefits are lousy, and the specialty care you’ll need most — dental, vision, hearing and long-term care — are not covered in the basic package. It’s as if Medicare was designed by pranksters, and we’re paying the price now as the percentage of the 65-and-up population explodes.
So what are people supposed to do as they get older and their teeth get looser?
A retired friend told me that she and her husband don’t have dental insurance because it costs too much and covers too little, and it turns out they’re not alone. By some estimates, half of U.S. residents 65 and older have no dental insurance.
That’s actually not a bad option, said Mertz, given the cost of insurance premiums and co-pays, along with the caps. And even if you’ve got insurance, a lot of dentists don’t accept it because the reimbursements have stagnated as their costs have spiked.
But without insurance, a lot of people simply don’t go to the dentist until they have to, and that can be dangerous.
“Dental problems are very clearly associated with diabetes,” as well as heart problems and other health issues, said Paul Glassman, associate dean of the California Northstate University dentistry school.
There is one other option, and Mertz referred to it as dental tourism, saying that Mexico and Costa Rica are popular destinations for U.S. residents.
“You can get a week’s vacation and dental work and still come out ahead of what you’d be paying in the U.S.,” she said.
Tijuana dentist Dr. Oscar Ceballos told me that roughly 80% of his patients are from north of the border, and come from as far away as Florida, Wisconsin and Alaska. He has patients in their 80s and 90s who have been returning for years because in the U.S. their insurance was expensive, the coverage was limited and out-of-pocket expenses were unaffordable.
“For example, a dental implant in California is around $3,000-$5,000,” Ceballos said. At his office, depending on the specifics, the same service “is like $1,500 to $2,500.” The cost is lower because personnel, office rent and other overhead costs are cheaper than in the U.S., Ceballos said.
As we spoke by phone, Ceballos peeked into his waiting room and said three patients were from the U.S. He handed his cellphone to one of them, San Diegan John Lane, who said he’s been going south of the border for nine years.
“The primary reason is the quality of the care,” said Lane, who told me he refers to himself as 39, “with almost 40 years of additional” time on the clock.
Ceballos is “conscientious and he has facilities that are as clean and sterile and as medically up to date as anything you’d find in the U.S.,” said Lane, who had driven his wife down from San Diego for a new crown.
“The cost is 50% less than what it would be in the U.S.,” said Lane, and sometimes the savings is even greater than that.
Come this summer, Lane may be seeing even more Californians in Ceballos’ waiting room.
“Proposed funding cuts to the Medi-Cal Dental program would have devastating impacts on our state’s most vulnerable residents,” said dentist Robert Hanlon, president of the California Dental Assn.
Dental student Somkene Okwuego smiles after completing her work on patient Jimmy Stewart, 83, who receives affordable dental work at the Ostrow School of Dentistry of USC on the USC campus in Los Angeles on February 26, 2026.
(Genaro Molina / Los Angeles Times)
Under Proposition 56’s tobacco tax in 2016, supplemental reimbursements to dentists have been in place, but those increases could be wiped out under a budget-cutting proposal. Only about 40% of the state’s dentists accept Medi-Cal payments as it is, and Hanlon told me a CDA survey indicates that half would stop accepting Medi-Cal patients and many others will accept fewer patients.
“It’s appalling that when the cost of providing healthcare is at an all-time high, the state is considering cutting program funding back to 1990s levels,” Hanlon said. “These cuts … will force patients to forgo or delay basic dental care, driving completely preventable emergencies into already overcrowded emergency departments.”
Somkene Okwuego, who as a child in South L.A. was occasionally a patient at USC’s Herman Ostrow School of Dentistry clinic, will graduate from the school in just a few months.
I first wrote about Okwuego three years ago, after she got an undergrad degree in gerontology, and she told me a few days ago that many of her dental patients are elderly and have Medi-Cal or no insurance at all. She has also worked at a Skid Row dental clinic, and plans after graduation to work at a clinic where dental care is free or discounted.
Okwuego said “fixing the smiles” of her patients is a privilege and boosts their self-image, which can help “when they’re trying to get jobs.” When I dropped by to see her Thursday, she was with 83-year-old patient Jimmy Stewart.
Stewart, an Army veteran, told me he had trouble getting dental care at the VA and had gone years without seeing a dentist before a friend recommended the Ostrow clinic. He said he’s had extractions and top-quality restorative care at USC, with the work covered by his Medi-Cal insurance.
I told Stewart there could be some Medi-Cal cuts in the works this summer.
“I’d be screwed,” he said.
Him and a lot of other people.
steve.lopez@latimes.com
Science
Diablo Canyon clears last California permit hurdle to keep running
Central Coast Water authorities approved waste discharge permits for Diablo Canyon nuclear plant Thursday, making it nearly certain it will remain running through 2030, and potentially through 2045.
The Pacific Gas & Electric-owned plant was originally supposed to shut down in 2025, but lawmakers extended that deadline by five years in 2022, fearing power shortages if a plant that provides about 9 percent the state’s electricity were to shut off.
In December, Diablo Canyon received a key permit from the California Coastal Commission through an agreement that involved PG&E giving up about 12,000 acres of nearby land for conservation in exchange for the loss of marine life caused by the plant’s operations.
Today’s 6-0 vote by the Central Coast Regional Water Board approved PG&E’s plans to limit discharges of pollutants into the water and continue to run its “once-through cooling system.” The cooling technology flushes ocean water through the plant to absorb heat and discharges it, killing what the Coastal Commission estimated to be two billion fish each year.
The board also granted the plant a certification under the Clean Water Act, the last state regulatory hurdle the facility needed to clear before the federal Nuclear Regulatory Commission (NRC) is allowed to renew its permit through 2045.
The new regional water board permit made several changes since the last one was issued in 1990. One was a first-time limit on the chemical tributyltin-10, a toxic, internationally-banned compound added to paint to prevent organisms from growing on ship hulls.
Additional changes stemmed from a 2025 Supreme Court ruling that said if pollutant permits like this one impose specific water quality requirements, they must also specify how to meet them.
The plant’s biggest water quality impact is the heated water it discharges into the ocean, and that part of the permit remains unchanged. Radioactive waste from the plant is regulated not by the state but by the NRC.
California state law only allows the plant to remain open to 2030, but some lawmakers and regulators have already expressed interest in another extension given growing electricity demand and the plant’s role in providing carbon-free power to the grid.
Some board members raised concerns about granting a certification that would allow the NRC to reauthorize the plant’s permits through 2045.
“There’s every reason to think the California entities responsible for making the decision about continuing operation, namely the California [Independent System Operator] and the Energy Commission, all of them are sort of leaning toward continuing to operate this facility,” said boardmember Dominic Roques. “I’d like us to be consistent with state law at least, and imply that we are consistent with ending operation at five years.”
Other board members noted that regulators could revisit the permits in five years or sooner if state and federal laws changes, and the board ultimately approved the permit.
Science
Deadly bird flu found in California elephant seals for the first time
The H5N1 bird flu virus that devastated South American elephant seal populations has been confirmed in seals at California’s Año Nuevo State Park, researchers from UC Davis and UC Santa Cruz announced Wednesday.
The virus has ravaged wild, commercial and domestic animals across the globe and was found last week in seven weaned pups. The confirmation came from the U.S. Department of Agriculture’s National Veterinary Services Laboratory in Ames, Iowa.
“This is exceptionally rapid detection of an outbreak in free-ranging marine mammals,” said Professor Christine Johnson, director of the Institute for Pandemic Insights at UC Davis’ Weill School of Veterinary Medicine. “We have most likely identified the very first cases here because of coordinated teams that have been on high alert with active surveillance for this disease for some time.”
Since last week, when researchers began noticing neurological and respoiratory signs of the disease in some animals, 30 seals have died, said Roxanne Beltran, a professor of ecology and evolutionary biology at UC Santa Cruz. Twenty-nine were weaned pups and the other was an adult male. The team has so far confirmed the virus in only seven of the dead pups.
Infected animals often have tremors convulsions, seizures and muscle weakness, Johnson said.
Beltran said teams from UC Santa Cruz, UC Davis and California State Parks monitor the animals 260 days of the year, “including every day from December 15 to March 1” when the animals typically come ashore to breed, give birth and nurse.
The concerning behavior and deaths were first noticed Feb. 19.
“This is one of the most well-studied elephant seal colonies on the planet,” she said. “We know the seals so well that it’s very obvious to us when something is abnormal. And so my team was out that morning and we observed abnormal behaviors in seals and increased mortality that we had not seen the day before in those exact same locations. So we were very confident that we caught the beginning of this outbreak.”
In late 2022, the virus decimated southern elephant seal populations in South America and several sub-Antarctic Islands. At some colonies in Argentina, 97% of pups died, while on South Georgia Island, researchers reported a 47% decline in breeding females between 2022 and 2024. Researchers believe tens of thousands of animals died.
More than 30,000 sea lions in Peru and Chile died between 2022 and 2024. In Argentina, roughly 1,300 sea lions and fur seals perished.
At the time, researchers were not sure why northern Pacific populations were not infected, but suspected previous or milder strains of the virus conferred some immunity.
The virus is better known in the U.S. for sweeping through the nation’s dairy herds, where it infected dozens of dairy workers, millions of cows and thousands of wild, feral and domestic mammals. It’s also been found in wild birds and killed millions of commercial chickens, geese and ducks.
Two Americans have died from the virus since 2024, and 71 have been infected. The vast majority were dairy or commercial poultry workers. One death was that of a Louisiana man who had underlying conditions and was believed to have been exposed via backyard poultry or wild birds.
Scientists at UC Santa Cruz and UC Davis increased their surveillance of the elephant seals in Año Nuevo in recent years. The catastrophic effect of the disease prompted worry that it would spread to California elephant seals, said Beltran, whose lab leads UC Santa Cruz’s northern elephant seal research program at Año Nuevo.
Johnson, the UC Davis researcher, said the team has been working with stranding networks across the Pacific region for several years — sampling the tissue of birds, elephant seals and other marine mammals. They have not seen the virus in other California marine mammals. Two previous outbreaks of bird flu in U.S. marine mammals occurred in Maine in 2022 and Washington in 2023, affecting gray and harbor seals.
The virus in the animals has not yet been fully sequenced, so it’s unclear how the animals were exposed.
“We think the transmission is actually from dead and dying sea birds” living among the sea lions, Johnson said. “But we’ll certainly be investigating if there’s any mammal-to-mammal transmission.”
Genetic sequencing from southern elephant seal populations in Argentina suggested that version of the virus had acquired mutations that allowed it to pass between mammals.
The H5N1 virus was first detected in geese in China in 1996. Since then it has spread across the globe, reaching North America in 2021. The only continent where it has not been detected is Oceania.
Año Nuevo State Park, just north of Santa Cruz, is home to a colony of some 5,000 elephant seals during the winter breeding season. About 1,350 seals were on the beach when the outbreak began. Other large California colonies are located at Piedras Blancas and Point Reyes National Sea Shore. Most of those animals — roughly 900 — are weaned pups.
It’s “important to keep this in context. So far, avian influenza has affected only a small proportion of the weaned at this time, and there are still thousands of apparently healthy animals in the population,” Beltran said in a press conference.
Public access to the park has been closed and guided elephant seal tours canceled.
Health and wildlife officials urge beachgoers to keep a safe distance from wildlife and keep dogs leashed because the virus is contagious.
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