Science
1 gene, 1 disease no more – acknowledging the full complexity of genetics could improve and personalize medicine
Genetic disease development is influenced by multiple variants, not just a single mutation. Research indicates that primary mutations interact with secondary variants, affecting symptom severity. This complexity necessitates broader genomic understanding for better disease prediction and personalized medical care.
Last Updated on October 13, 2025 by Daily News Staff
Santhosh Girirajan, Penn State
Genetic inheritance may sound straightforward: One gene causes one trait or a specific illness. When doctors use genetics, it’s usually to try to identify a disease-causing gene to help guide diagnosis and treatment. But for most health conditions, the genetics is far more complicated than how clinicians are currently looking at it in diagnosis, counseling and treatment.
Your DNA carries millions of genetic variants you inherit from your parents or develop by chance. Some are common variants, shared by many people. Others are rare variants, found in very few people or even unique to a family. Together, these variants shape who you are – from visible traits such as height or eye color to health conditions such as diabetes or heart disease.
In our newly published research in the journal Cell, my team and I found that a genetic mutation involved in neurodevelopmental and psychiatric conditions such as autism and schizophrenia is affected by multiple other genetic variants, changing how these conditions develop. Our findings support the idea that, rather than focusing on single genes, taking the whole genome into account would provide insight into how researchers understand what makes someone genetically predisposed to certain diseases and how those diseases develop.
Primary and secondary variants
Certain rare variants can cause problems on their own, such as the genetic mutations that cause sickle cell anemia and cystic fibrosis. But in many cases, whether someone actually develops symptoms of disease depends on what else is happening across the genome.
While a primary variant might trigger a disease, secondary variants can alter how that disease develops and progresses. Think of it like a song: The melody (primary variant) is the main part of the song, but the bassist and drummer (secondary variants) can change its groove and rhythm.
That’s why two people with the same genetic mutation can seem so different. One person might have severe symptoms, another person mild symptoms, and another none at all. These variations can even occur within the same family. This phenomenon, called variable expressivity, arises from differences in the secondary variants a person has. In most cases, these variants amplify the effects of the primary mutation. A higher number of secondary variants on top of a primary variant generally leads to more severe disease. https://www.youtube.com/embed/D0XYWKm_LoM?wmode=transparent&start=0 Mutations are a source of genetic variation.
Sometimes, a primary variant and a secondary variant together can cause two different disorders in the same person, such as Prader-Willi syndrome and Pitt-Hopkins syndrome. Other times, secondary variants have no obvious effect on their own but together can tip the balance of whether and how a disease will appear, even in the absence of a primary variant. This can be seen in the development of heart disease in children.
Insights from a missing piece of a chromosome
My team and I studied a genetic change known as a 16p12.1 deletion, where a small piece of chromosome 16 is missing. Researchers have linked this mutation to developmental delay, intellectual disability and psychiatric conditions such as schizophrenia. Yet most children inherit this genetic variant from a parent who has milder symptoms, different symptoms or sometimes no symptoms at all.
To understand why this happens, we analyzed 442 individuals from 124 families carrying this genetic mutation. We found that children lacking this piece of chromosome 16 had more secondary variants elsewhere in the genome compared to their carrier parents. These secondary variants took many forms, including both small changes and large deletions, duplications and expansions of their DNA.
Each type of secondary variant was associated with different health outcomes. Some were linked to smaller head size and reduced cognitive function, while others contributed to higher rates of psychiatric or developmental symptoms. This suggests that while a 16p12.1 deletion makes the genome more sensitive to neurodevelopmental disorders, which symptoms manifest depends on which other variants are present.
The story gets even more complex when considering the fact that children not only inherit a 16p12.1 deletion from one parent but also inherit secondary variants from both parents.
My team and I found that the symptoms of the parent with this genetic mutation often match those of their spouse. For example, a parent with a 16p12.1 deletion who shows signs of anxiety or depression is more likely to have a partner who also has these symptoms. This pattern, called assortative mating, means that when parents with overlapping genetic risks have children, those risks can combine and accumulate.
Over generations, this stacking of secondary variants can lead to children who have more severe symptoms than their parents.
Biases in genetics research
One reason why scientific understanding of secondary variants has lagged is that genetic research often depends on who is recruited to participate in these studies and how researchers recruit them.
Most studies recruit patients affected with a particular disease. Families recruited from genetic clinics typically have children with severe versions of the disease. But if studies focus only on patients with the most acute symptoms, researchers may overestimate the effects of primary variants and miss the subtler role that secondary variants may play in how a disease develops.
But if researchers were to study people drawn from the general population – say, by recruiting people from a large shopping mall – some might carry the same primary variant but have far milder symptoms or none at all. This variability allows researchers to better dissect how different parts of the genome interact with each other and affect how a disease develops.
In our study, for example, we found that people with a 16p12.1 deletion who were recruited from the general population often had milder symptoms and different patterns of secondary variants compared to those who were recruited in a clinic.
Embracing complexity in genetics
Instead of a deterministic view where one mutation equals one outcome, a more complex model accounts for the fact that whether and how a disease develops depends on the interplay between different genetic variants and environment. This has implications for how genetics is used in the clinic.
Currently, a child who tests positive for a genetic variant might be diagnosed with a disease tied to that mutation. In the future, doctors might also examine the child’s broader genetic profile to better predict their developmental trajectory, psychiatric risk or response to therapies. Families could be counseled with a more realistic picture of their child’s probability of developing a disease, rather than assuming every person with the same genetic variant will share the same outcome.
The science is still emerging. Larger and more diverse datasets and models that can better capture the subtle effects of genetic variants and environmental factors are still needed. But what’s clear is that secondary variants are not secondary in importance.
By embracing this complexity, I believe genetics can move closer to its ultimate promise: not just explaining why disease happens, but predicting who is most at risk and personalizing care for each individual.
Santhosh Girirajan, Professor of Biochemistry, Molecular Biology and Genomics, Penn State
This article is republished from The Conversation under a Creative Commons license. Read the original article.
STM Daily News is a vibrant news blog dedicated to sharing the brighter side of human experiences. Emphasizing positive, uplifting stories, the site focuses on delivering inspiring, informative, and well-researched content. With a commitment to accurate, fair, and responsible journalism, STM Daily News aims to foster a community of readers passionate about positive change and engaged in meaningful conversations. Join the movement and explore stories that celebrate the positive impacts shaping our world.
Science
Sonic booms from meteors can release the energy of hundreds of tons of TNT – here’s how they work
Shawn Laatsch, University of Maine
Sonic booms from meteors can release the energy of hundreds of tons of TNT – here’s how they work
As humans, we live out our lives on a planet that is constantly sweeping through a cosmic ocean littered with ancient debris from the formation of the solar system. For the most part, our world glides silently through space, shielded by Earth’s thin atmosphere.
Occasionally, however, the rest of the universe reminds us of its presence with stunning, visceral clarity.
Residents along the Massachusetts–New Hampshire border were startled by a sudden sonic boom on the afternoon of May 30, 2026. A large number of people up and down the Eastern Seaboard witnessed it.
After NASA analyzed imagery from weather satellites, they identified the culprit as a small meteor measuring roughly 3 to 5 feet (1 to 2 meters) across. It was screaming through space at an astonishing 42,000 miles per hour (68,000 kilometers per hour) when it plunged into Earth’s upper atmosphere.
Friction between the meteor and the increasingly dense air quickly turned the kinetic energy of the rock shooting through the sky into blistering heat. At an altitude of roughly 40 miles (60 kilometers), the immense heat and pressure overcame the structural integrity of the meteor, causing it to fragment in a brilliant flash.
The breakup released a staggering burst of energy equivalent to 300 tons of TNT. When an object travels through the air at speeds faster than sound, which is 761 mph (1,225 kph), it creates a shock wave creating a thunderous clap, or sonic boom. While the majority of the rock vaporized, the remaining fragments rained down harmlessly into the waters of Cape Cod Bay.
In the past, such an event might have passed as an unverified sighting in the daytime sky. Today, however, our planet is wired with an accidental network of planetary defense sensors: dashboard cameras, security systems and digital doorbells.
Because meteor entries like this one last only a few fleeting seconds, they were easily missed in the past. Now, our collective digital eyes capture these spontaneous cosmic intrusions almost instantly, bringing the universe directly into our daily news feeds. While dramatic, these events are more common than most people imagine.
As someone who has worked as a planetarium director and astronomy educator for over four decades, I often get emails, social media messages and phone calls about such objects and sightings. While hearing a sonic boom can be a bit unsettling or even shocking, it reminds us we live in an active universe and may want to occasionally look up instead of down at our devices.
A meteoric spring
The Cape Cod fireball was the latest sighting in an active season of meteoritic arrivals. Just months earlier, the solar system seemed to be sending a parade of rocky objects down to Earth.
From March 8-11, observers in Northern Europe witnessed large, slow-moving fireballs in their skies. Enthusiasts and scientists successfully recovered several fragments. Lab analysis of these specimens revealed their place in a fascinating lineage – scientists determined that they had originated from Vesta, a massive, pristine asteroid orbiting between Mars and Jupiter.
On March 17, a 7-ton asteroid measuring roughly 6 feet across entered the atmosphere directly over Lake Erie. Traveling at 45,000 mph (72,400 kph), it generated a brilliant daytime flash and a powerful sonic boom, unloading an energy equivalent to 250 tons of TNT. NASA scientists published data about its trajectory, allowing meteorite hunters to recover pristine fragments in Valley City, just a short drive from Cleveland, Ohio.
Only four days later, on March 21, another cosmic fragment blazed across the skies of Texas. This object was about 3 feet wide, and it traveled at 35,000 mph (56,300 kph), releasing the energy of roughly 26 tons of TNT.
Outside of Houston, homeowner Sherri James was startled by a sudden crash, only to discover a 6-inch (15-cm) hole in her roof and a small piece of the solar system resting on her floor.
Thank goodness for Earth’s atmospheric shield
The benchmark for modern atmospheric impacts is the Chelyabinsk meteor, which exploded over Russia on Feb. 15, 2013.
That object was significantly larger than any of the meteors researchers have observed in 2026, measuring 60 feet (18 m) across and weighing roughly 10,000 tons. When it shattered 18 miles (29 km) above the ground, it produced an airburst with an explosive force 30 times greater than the Hiroshima atomic bomb.
The resulting shock wave shattered glass across hundreds of square miles, injuring nearly 1,500 people and registering as a seismic event between 2.7 and 3.7 on the Richter scale. The incident was a stark reminder that while Earth’s atmosphere is an incredibly effective shield, absorbing the lion’s share of cosmic impacts, a large enough kinetic punch can still reach the surface below.
Despite the dramatic stories around these meteor impacts, history shows that the cosmic lottery rarely targets humans directly. In all of recorded history, there is only one universally confirmed case of a person being directly struck by a space rock.
In 1954, an 8.5-pound (3.8 kg) meteorite crashed through the roof of a house in Sylacauga, Alabama, ricocheted off a heavy wooden radio and struck a sleeping woman named Ann Hodges. Though it left a severe bruise on her hip, the radio absorbed the brunt of the impact. Had it not been for the radio, there is a chance she could have been seriously injured or killed by this object.
Living with the cosmos
So, are you in any imminent danger from meteors? The mathematics of the cosmos provide profound reassurance. The statistical odds of being struck by a meteorite are vanishingly small. You stand a better chance of winning a multimillion-dollar lottery jackpot 10 times in a row than ever being hit by a meteorite.
The vast majority of the tons of space debris that bombard Earth daily arrive as harmless dust grains, burning up as elegant meteors or shooting stars. But when the larger pieces do break through and land on our planet, they offer a rare, tangible connection to the beginning of the solar system.
If you ever happen to witness one of these magnificent fireballs ripping open the sky, consider reporting your observation to the American Meteor Society. The organization keeps track of sightings and falls from around the globe. Recovered fragments provide a way for scientists to gain valuable information about the origin of our solar system, and of our home planet.
Shawn Laatsch, Director of the Versant Power Astronomy Center, University of Maine
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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Last Updated on June 12, 2026 by Rod Washington
Valerie Thomas is a true pioneer in the world of science and technology. A NASA engineer and physicist, she is best known for inventing the illusion transmitter, a groundbreaking device that creates 3D images using concave mirrors. This invention laid the foundation for modern 3D imaging and virtual reality technologies.
Beyond her inventions, Thomas broke barriers as an African American woman in STEM, mentoring countless young scientists and advocating for diversity in science and engineering. Her work at NASA’s Goddard Space Flight Center helped advance satellite technology and data visualization, making her contributions both innovative and enduring.
In our latest short video, we highlight Valerie Thomas’ remarkable journey—from her early passion for science to her groundbreaking work at NASA. Watch and be inspired by a true STEM pioneer whose legacy continues to shape the future of space and technology.
🎥 Watch the video here: https://youtu.be/P5XTgpcAoHw
Dive into “The Knowledge,” where curiosity meets clarity. This playlist, in collaboration with STMDailyNews.com, is designed for viewers who value historical accuracy and insightful learning. Our short videos, ranging from 30 seconds to a minute and a half, make complex subjects easy to grasp in no time. Covering everything from historical events to contemporary processes and entertainment, “The Knowledge” bridges the past with the present. In a world where information is abundant yet often misused, our series aims to guide you through the noise, preserving vital knowledge and truths that shape our lives today. Perfect for curious minds eager to discover the ‘why’ and ‘how’ of everything around us. Subscribe and join in as we explore the facts that matter. https://stmdailynews.com/the-knowledge/
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Forgotten Genius Fridays is a weekly collection of short videos and articles dedicated to inventors, innovators, scientists, and creators whose impact changed the world—but whose names were often left out of the textbooks.
From life-saving inventions and cultural breakthroughs to game-changing ideas buried by bias, our series digs up the truth behind the minds that mattered.
Each episode of The Knowledge runs 30–90 seconds, designed for curious minds on the go—perfect for YouTube Shorts, TikTok, Reels, and quick reads.
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Automotive
The Road to Cleaner Water: How to Prevent Roads from Polluting Waterways
Everyone loves driving on clean highways and spotless local roads. Few people, however, realize the benefits of clean roads go well beyond mere aesthetics. Cleaner roads also mean cleaner and healthier local rivers, lakes and beaches. Follow these simple year-round tips to help make the waters as fun and healthy as possible this summer.
(Feature Impact) Everyone loves driving on clean highways and spotless local roads. Few people, however, realize the benefits of clean roads go well beyond mere aesthetics. Cleaner roads also mean cleaner and healthier local rivers, lakes and beaches.
That’s because harmful pollutants in local waters often run off untreated from highways and roads during strong storms. Those rains sweep trash, dripped oil, harmful chemicals and even dangerous bacteria from pet waste into local waters via stormways and sewers. This untreated runoff can affect people’s health, make water unsafe for swimming and harm aquatic life. Every year, such man-made “stormwater pollution” even closes portions of recreational rivers and beaches.
It’s up to everyone to help prevent human-caused stormwater pollution. Don’t wait for rain in the forecast to get started. Instead, follow these simple year-round tips from the experts at the California Department of Transportation to help make the cooling waters in California and beyond as fun and healthy as possible this summer.
Trash-Free Trips and Responsible Car Care
Summer can mean more road time traveling to your next adventure. Loose items in truck beds and on roof carriers or trash tossed from car windows can quickly become the next wave of stormwater pollution flowing into local waters. To reduce:
- Secure Your Load: Always securely tarp and tie down anything in a truck bed or on a roof rack. Items falling off vehicles are both a safety hazard and can become roadside debris.
- Keep a Car Trash Catcher: Designate a bag or container in your car for food wrappers, coffee cups and other small trash until you can dispose of it properly.
- Wash Smart: Commercial car washes that recycle water are superior for preventing road dirt and chemicals accumulated on your car from entering storm drains compared to washing in a driveway. If washing at home, do it on your lawn or a permeable surface where the water naturally filters into the ground and not street gutters.
Outdoor Adventures That Leave Only Footprints
Whether you’re hiking a mountain trail, picnicking at the park or relaxing on the beach, remember the outdoor golden rule: pack out everything you pack in. Food wrappers, plastic bottles and even seemingly small items like bottle caps and cigarette butts are some of the most common litter found in parks, waterways and along coastlines. When left behind, they’re not just eyesores; they’re prime candidates for being washed into waterways.
- Pro Tip: Choose reusable water bottles that clip onto bags to reduce pollution from discarded plastic bottles.
At Home and In Your Neighborhood
Even close to home, your actions can make a difference.
- Garden Care: When tidying up your garden or front lawn, sweep leaves and grass clippings into your green bin instead of hosing them down the driveway. Hosing yard waste into road gutters can clog storm drains and cause flooding.
- Pesticide Prevention: To protect waterways from harmful chemical runoff, opt for organic or eco-friendly alternatives for pest and weed control whenever possible.
- Scoop the Poop: Pet waste contains harmful bacteria that can contaminate waterways. In fact, the EPA estimates that just two days’ worth of waste from 100 dogs can produce enough bacteria to close a beach. Always pick up after your pets, especially when walking in your neighborhood or parks, and dispose of it in a trash bin.
Pollution in waterways doesn’t just look bad; it creates real problems, from harming wildlife and ecosystems to causing potential health issues for humans and pets who encounter contaminated water. The cleaner roads and surrounding areas are, the healthier rivers, lakes and beaches become. For more tips and resources, visit CleanWaterCA.com to ensure a clean, healthy summer for everyone.
Photos courtesy of Shutterstock
SOURCE:
California Department of Transportation
STM Daily News is a vibrant news blog dedicated to sharing the brighter side of human experiences. Emphasizing positive, uplifting stories, the site focuses on delivering inspiring, informative, and well-researched content. With a commitment to accurate, fair, and responsible journalism, STM Daily News aims to foster a community of readers passionate about positive change and engaged in meaningful conversations. Join the movement and explore stories that celebrate the positive impacts shaping our world.
