N6-methyladenosine in inflammatory bowel disease: An emerging regulator of pathogenesis and a novel therapeutic frontier.
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Updates every hour. Last Updated: 21-Oct-2026 21:17 ET (22-Oct-2026 01:17 GMT/UTC)
UC San Diego biologists have unraveled the genetic adaptation that gave butterflies the ability to see rich, vivid color in their environment. The genetic change produces an additional photoreceptor that expands color vision for locating nectar and other butterflies.
A study led by researchers at NYU Grossman School of Medicine identified shared molecular patterns in human milk that link maternal nutrition, mammary gland biology, and infant growth.
Why do large dogs tend to live shorter lives than their smaller counterparts? According to a new study of nearly 900 dogs, the answer may be written into their epigenome. The findings reveal that larger and male dogs undergo accelerated molecular aging, with pronounced DNA methylation (DNAm) on the X chromosome and at transposable elements (TEs). Aging is a universal process, but its pace and biological mechanisms substantially differ between individuals and species. Domestic dogs offer a particularly useful model for understanding the biology of aging because their lifespans vary dramatically with body size. For example, smaller breeds can live nearly twice as long as larger breeds. Moreover, companion dogs also live in human environments, consume commercial diets, and receive routine medical care, making them a relevant translational model for studying how genetic background and environmental exposures shape aging. However, how intrinsic factors such as size and biological sex influence variation in dog aging and lifespan remains unclear. Previous research has demonstrated that DNAm is a useful indicator of biological aging, with “epigenetic clocks” offering a way to understand the factors that accelerate or decelerate biological aging.
Blaise Mariner and colleagues generated 1,640 methylomes from a cohort of 894 dogs in the Dog Aging Project. They combined these molecular data with detailed genetic and demographic data. Mariner et al. found that molecular aging occurs most rapidly early in a dog’s life. What’s more, larger and male dogs – both of which have shorter lifespans than their respective counterparts – age more quickly at the molecular level. The authors identified different epigenetic patterns underlying these effects. According to the findings, sex-related changes were concentrated on the X chromosome, while body-size-related changes were especially prominent in TEs, stretches of DNA that can influence genome stability and gene regulation.
Not only do big dogs die younger but they are also more susceptible to many age-related diseases. And what scientists can learn about dog aging can provide an important window into human aging too.
Now we may know why.
A new study led by researchers at Arizona State University offers the first compelling molecular explanation of why large dogs live shorter lives: the answer may lie in how hallmarks of aging reshape dog DNA.
Researchers successfully built a time-calibrated lineage tree showing how a single cell turned into 1.28 million—about 10% of the cells in a two-week-old mouse embryo. This is by far the largest lineage tree ever built for a mammal.