Science
A tiny fern with a big secret just got into the Guinness Book of World Records
Tmesipteris oblanceolata is an obscure species of fork fern found in New Caledonia, a French territory in the South Pacific. Just 4 to 6 inches tall, the humble plant is, in one particular way, the most remarkable living thing in the world.
“You would walk over it. You might even tread on it without knowing it,” said Ilia Leitch, a plant evolutionary biologist and senior research leader at the U.K.’s Royal Botanic Gardens, Kew. “But it houses within it this great secret.”
Recently, T. oblanceolata entered the Guinness Book of World Records after a team of scientists determined that the wispy fern has the biggest known genome of any living organism. Crammed into the nucleus of every one of its cells are 160.45 billion base pairs — 160.45 billion rungs on the twirling double-helix ladder that is the plant’s DNA.
T. oblanceolata has more genes than the mighty California redwood (Sequoia sempervirens) or the massive blue whale (Balaenoptera musculus). It has 50 times more DNA than Homo sapiens, the species that figured out what DNA is in the first place. The findings were published in the journal iScience.
“We were absolutely astonished when we found out how big this genome was,” said botanist Jaume Pellicer of Institut Botànic de Barcelona in Spain, a co-author of the study along with Leitch. “We already knew about the existence of giant genomes in the genus but did not anticipate that the one in Tmesipteris oblanceolata was going to beat any previous records.”
A genome contains all the information cells need to direct the growth and development of the organism. But life doesn’t offer up instructions in the tidy, more-steps-equals-more-complexity way of Ikea or Lego assembly manuals — hence petite ferns with jumbo-sized genetic codes.
You might step on T. oblanceolata “without knowing it,” a plant evolutionary biologist said. (Photographs by Pol Fernandez and Oriane Hidalgo)
Measuring genome size is “not a way to measure genome complexity or coding capacity,” said Elliot Meyerowitz, a Caltech biologist who was not involved in the research.
Only a minuscule sliver of the genetic material that most plant and animal cells lug around actually contains direct instructions for how to make the building blocks that make up living things. Less than 2% of the human genome actually codes for proteins. For the fork fern, the research team estimates that less than 1% of its genome does.
The rest is known as noncoding DNA. Understanding what that noncoding genetic material does and why cells haul it around are among the biggest questions in evolutionary biology.
Half a century ago, scientists dismissed this noncoding stuff as “junk DNA,” a term now considered “a reflection of our own ignorance,” Leitch said.
It’s not that it all does nothing, she said. We just don’t yet understand everything that it does.
T. oblanceolata ferns grow amid tangled branches and fallen leaves.
(Jaume Pellicer)
In recent years, researchers have found that manipulating or deleting some of these noncoding sequences affect gene expression. This suggests that at least some of this material plays a role in the processes that “switch” genes on and off, “like the conductor of an orchestra, saying who comes in here and who should be quiet here,” Leitch said.
This intricate choreography of gene expression is how we get the incredible diversity within our own species and across the kingdoms of living things.
“Understanding how these genomes function and are structured represents the ultimate milestone in this field of research,” Pellicer wrote in an email. “But for now, it is like trying to read a book of instructions without even knowing where page one is!”
T. oblanceolata displaces the previous genome record holder, a modestly sized flowering plant called Paris japonica that has 149 billion base pairs. While there may be something else out there packing a bigger genetic punch, botanists believe these plants are at the upper end of how much DNA a living thing can have.
A researcher looks for fork ferns in New Caledonia.
(Oriane Hidalgo)
“If it’s not the biggest, it’s jolly well close to it,” Leitch said of the fork fern’s genome. “There are so many consequences associated with having so much DNA that I think we’re at the limits of what biology can cope with.”
An organism has to divide its cells in order to grow, and before it can do that it has to make a copy of all the DNA in its cells. Copying a colossal genome is a big investment of time, energy and nutrients, Leitch pointed out. For plants, bigger genomes are associated with slower growth and less efficient photosynthesis.
As a result, organisms with massive genomes tend to be found in stable environments without much competition, Leitch said. That’s true of T. oblanceolata, slow-growing Paris japonica and the marbled lungfish, holder of the animal kingdom’s largest genome (nearly 130 billion base pairs).
Unfortunately for T. oblanceolata, stable conditions are increasingly hard to come by in a rapidly changing climate.
“As long as they’re stable, as long as things don’t change, selection won’t weed them out, so to speak,” Leitch said. “I would predict that if the environment changed, they would not be in a good position.”
Science
There were 13 full-service public health clinics in L.A. County. Now there are 6
Because of budget cuts, the Los Angeles County Department of Public Health has ended clinical services at seven of its public health clinic sites.
As of Feb. 27, the county is no longer providing services such as vaccinations, sexually transmitted infection testing and treatment, or tuberculosis diagnosis and specialty TB care at the affected locations, according to county officials and a department fact sheet.
The sites losing clinical services are Antelope Valley in Lancaster; the Center for Community Health (Leavy) in San Pedro, Curtis R. Tucker in Inglewood, Hollywood-Wilshire, Pomona, Dr. Ruth Temple in South Los Angeles, and Torrance. Services will continue to be provided by the six remaining public health clinics, and through nearby community clinics.
The changes are the result of about $50 million in funding losses, according to official county statements.
“That pushed us to make the very difficult decision to end clinical services at seven of our sites,” said Dr. Anish Mahajan, chief deputy director of the L.A. County Department of Public Health.
Mahajan said the department selected clinics with relatively lower patient volumes. Over the last month, he said, the department has sent letters to patients about the changes, and referred them to unaffected county clinics, nearby federally qualified health centers or other community providers. According to Mahajan, for tuberculosis patients, particularly those requiring directly observed therapy, public health nurses will continue visiting patients.
Public health clinics form part of the county’s healthcare safety net, serving low-income residents and those with limited access to care. Officials said that about half of the patients the county currently sees across its clinics are uninsured.
Mahajan noted that the clinics were established decades ago, before the Affordable Care Act expanded Medi-Cal coverage and increased the number of federally qualified health centers. He said that as more residents gained access to primary care, utilization at some county-run clinics declined.
“Now that we have a more sophisticated safety net, people often have another place to go for their full range of care,” he said.
Still, the closures have unsettled providers who work closely with local vulnerable populations.
“I hate to see any services that serve our at-risk and homeless community shut down,” said Mark Hood, chief executive of Union Rescue Mission in downtown Los Angeles. “There’s so much need out there, so it always is going to create hardship for the people that actually need the help the most.”
Union Rescue Mission does not receive government funding for its healthcare services, Hood said. The mission’s clinics are open not only to shelter guests, up to 1,000 people nightly, but also to people living on the streets who walk in seeking care.
Its dental clinic alone sees nearly 9,000 patients a year, Hood said.
“We haven’t seen it yet, but I expect in the coming days and weeks we’ll see more people coming through our doors looking for help,” he said. “They’re going to have to find help somewhere.” Hood said women experiencing homelessness are especially vulnerable when preventive care, including sexual and reproductive health services, becomes harder to access.
County officials said staffing impacts so far have been managed through reassignment rather than layoffs. Roughly 200 to 300 positions across the department have been eliminated amid funding cuts, officials said, though many were vacant. About 120 employees whose positions were affected have been reassigned; according to Mahajan, no one has been laid off.
The clinic closures come amid broader fiscal uncertainty. Mahajan said that due to the Trump administration’s “Big Beautiful Bill,” Los Angeles County could lose $2.4 billion over the next several years. That funding, he said, supports clinics, hospitals and community clinic partners now absorbing patients who previously went to the clinics that closed on Feb. 27.
In response, the L.A. County Board of Supervisors has backed a proposed half-cent sales tax measure that would generate hundreds of millions of dollars annually for healthcare and public health services. Voters are expected to consider the measure in June.
Science
Mobile clinic brings mammograms to women on Skid Row
Sharon Horton stepped through the door of a sky-blue mobile clinic and onto a Skid Row sidewalk. She wore a yellow knit beanie, gold hoop earrings and the relieved grin of a woman who has finally checked a mammogram off her to-do list.
It had been years since her last breast cancer screening procedure. This one, which took place in City of Hope’s Cancer Prevention and Screening mobile clinic, was faster and easier. The staff was kind. The machine that X-rayed her breast was more comfortable than the cold hard contraption she remembered.
Relatively speaking, of course — it was still a mammogram.
“It’s like, OK, let me go already!” Horton, 68, said with a laugh.
The clinic was parked on South San Pedro Street in front of Union Rescue Mission, the nonprofit shelter where Horton resides. Within a week, City of Hope, a cancer research hospital, would share the results with Horton and Dr. Mary Marfisee, the mission’s family medical services director. If the mammogram detected anything of concern, they’d map out a treatment plan from there.
Naureen Sayani, 47, a resident of Union Rescue Mission, left, discusses her medical history with Adriana Galindo, a medical assistant, before getting a mammogram on last week.
(Kayla Bartkowski / Los Angeles Times)
“It’s very important to take care of your health, and you need to get involved in everything that you can to make your life a better life,” said Horton, who is looking forward to a forthcoming move into Section 8 housing.
Horton was one of the first patients of a new women’s health initiative from UCLA’s Homeless Healthcare Collaborative at Union Rescue Mission. Staffed by third-year UCLA Medical School students and led by Marfisee, a UCLA assistant clinical professor of family medicine, the clinic treats mission residents as well as unhoused people living in the surrounding neighborhood.
The new cancer screening project arrives at a time of dire financial pressures on county public health services.
Citing rising costs and a $50-million reduction in federal, state and local grant and contract income, the Los Angeles County Department of Public Health on Feb. 27 ended services at seven of 13 public clinics that provide vaccines, tests and treatment for sexually transmitted diseases and other services to housed and unhoused county residents.
Although Union Rescue Mission’s own funding comes mainly from private sources and is less imperiled by public cuts, the 135-year-old shelter expects the need for its services to rise, Chief Executive Mark Hood said.
Even as unsheltered homelessness declined for the last two years across Los Angeles County, the unsheltered population on Skid Row — long seen as the epicenter of the region’s homelessness crisis — grew 9% in 2024, the most recent year for which census data are available.
For many local women navigating daily concerns over housing, food and personal safety, “their own health is not a priority,” Marfisee said.
Those whose problems have become too serious to ignore face daunting obstacles to care. Marfisee recalled one patient who came to her with a lump in her breast and no identification.
In order to get a mammogram, Marfisee explained, the woman first needed to obtain a birth certificate, and then a state-issued identification card. Then she needed to enroll in Medi-Cal. After that, clinic staff helped her find a primary care physician who could order the imaging test.
Given the barriers to preventative care, homeless women die from breast cancer at nearly twice the rate of securely housed women, a 2019 study found. Marfisee’s own survey of the mission’s female residents found that nearly 90% were not up to date on recommended cancer screenings like mammograms and pap smears, which detect early cervical cancer.
To address this gap, Marfisee — a dogged patient advocate — reached out to City of Hope. The Duarte-based research and treatment center unveiled in March 2024 its first mobile cancer screening clinic, a moving van-sized clinic on wheels that it deploys to food banks and health centers, as well as to companies offering free mammograms as an employee benefit.
“In true Dr. Mary fashion, she saw the vision,” said Jessica Thies, the mobile screening program’s regional nursing director. After working through some logistical hurdles, the mission and City of Hope secured a date for the van’s first visit.
The next challenge was getting the word out to patients. Marfisee and her students walked through the surrounding neighborhood, went cot to cot in the women’s dorm and held two informational sessions in December and January to answer patients’ questions.
At the sessions, the team walked through the basics of who should get a mammogram (women age 40 or older, those with a family history of breast cancer) and the procedure itself. (“Like a tortilla maker?” one woman asked skeptically after hearing a description of the mammography unit.)
The medical students were able to dispel rumors some women had heard: The test doesn’t damage breast tissue, nor do the X-rays increase cancer risk. Others questioned a mammogram’s value: What good was it knowing they had cancer if they couldn’t get follow-up care?
On this latter point, Marfisee is determined not to let patients fall through the cracks.
Thirteen patients received mammograms at the van’s first visit on Wednesday. Within a week, City of Hope will contact patients with their results and send them to Marfisee and her team. She is already mentally mapping the next steps should any patient have a situation that requires a biopsy or further imaging: working with their case manager at the mission, calling in favors, wrangling with any insurance the patient might have.
“It’ll be a good fight,” Marfisee said, as residents in the adjacent cafeteria carried trays of sloppy joes and burgers to their lunch tables. “But we’ll just keep asking for help and get it done.”
Science
Can fire-resistant homes be sexy? ‘You be the judge,’ says this Palisades architect
At first glance, it looks like nothing more than a charming Spanish-revival, quintessentially Californian home — but this Pacific Palisades rebuild is constructed like a tank.
Every exterior wall of the steel-framed home is a foot-thick, fire-resistant barricade. The home is connected to a satellite fire monitoring service. Should a fire start in town, sturdy metal shutters descend to cover every window. An exterior sprinkler system can pump 40,000 gallons of water from giant tanks hidden behind the shrubs in the property’s yard. If the cameras and heat sensors around the house detect danger, the system can envelop the home in over 1,000 gallons of fire retardant and hundreds of gallons of fire-suppressing foam.
Palisades resident and architect Ardie Tavangarian is so confident in his design that he even asked the fire department if they could start a controlled fire on the property to test it all out. (They said no.)
Tavangarian built a career designing multimillion-dollar luxury homes in Los Angeles, but after the Palisades fire destroyed 13 of his works — including his family’s home — he found another calling: how to design a house that can handle what the Santa Monica Mountains throw at it. And how to do it quickly and affordably.
Water tanks form part of a backup water supply in a newly built fire-resistant home in Pacific Palisades.
“Nature is so powerful,” he said, sitting on a couch in the new house, which he built for his adult twin daughters. “We are guests living in that environment and expecting, ‘Oh, nature is going to be really kind to me.’ No, it’s not. It does what it’s supposed to do.”
Tavangarian watched the Jan. 1 Lachman fire from his property not far from here; a week later that fire rekindled, grew into the Palisades fire, and burned through his house. But the painful details of the fire — the missteps of the fire department, the empty reservoir — didn’t matter when it came to deciding how to rebuild, he said. The reality is, many fires have burned in these mountains. Many more will.
A sprinkler on the roof is part of a house-wide sprinkler system.
For the architect, who has spent much of his 45-year career designing for luxury, hardening a home against wildfire has brought a new kind of luxury to his homes: peace of mind.
It’s a sentiment that resonates with fire survivors: Tavangarian says he’s received considerable interest from other property owners in the Palisades looking to rebuild their houses.
The metal shutters and advanced outdoor sprinkler system are the flashiest parts of Tavangarian’s home hardening project, and the efficacy of these adaptations is still up for debate. Because the measures have not yet been widely adopted, there are few studies exploring how much or little they protect homes in real-world fires.
Architect Ardie Tavangarian inside the house he designed.
Anecdotal evidence has indicated the effectiveness of sprinklers can vary significantly based on the setup and the conditions during the fire. Extreme wind, for example, can make them less effective. Lab studies have generally found shutters can reduce the risk of windows shattering.
These measures aren’t cheap, either. Sprinkler systems can cost north of $100,000, for example. However, Tavangarian said when all was said and done, the home he built for his daughters cost around $700 per square foot — less than what Palisades residents said they expected to pay, but more than what Altadena residents expected for their rebuilds.
Tavangarian also hopes to see insurers increasingly consider the home-hardening measures property owners take when writing policies, which he said could potentially offset the extra cost in a decade or less. As he explored getting insurance for the new home, one insurer quoted him $80,000 a year. After he convinced the company to visit the property, it lowered the quote to just $13,000, he said.
The house includes metal heat shields that can drop down if a fire approaches.
The home also has essentially all of the other less flashy — but much cheaper and well-proven — home hardening measures recommended by fire professionals: The underside of the roof’s overhang is closed off — a common place embers enter a home. The roof, where burning embers can accumulate, is made of fire-resistant material. The windows, vulnerable to shattering in extreme heat, are made of a toughened glass. There is virtually no vegetation within the first five feet of the home.
When asked if he felt he had compromised on design, comfort or aesthetics for the extra protection — one of the many concerns Californians have with the state’s draft “Zone Zero” requirements that may significantly limit vegetation within five feet of a home — Tavangarian simply said, “You be the judge.”
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