There's Now a Third Way to Inherit Traits That Isn't Your DNA or RNA, Scientists Say

Yahoo

07-04-2025

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Most people know that inherited traits between generations is a genetic process, but a new study says other inheritable mechanisms may exist.
Scientists at the University of Toronto studying the hermaphroditic worm Caenorhabditis elegans found that amyloid-like structures—proteins often associated with diseases like Alzheimer's—can have inheritable traits.
This pathway, or others like it, could explain why some inheritable traits between generations can't be explained exclusively via DNA and RNA.
Containing some 3.2 billion base pairs, the human genome is far from a simple set of genetic instructions, but the process of inherited traits from parent to child is often described as a straightforward one. The genes of one parent combine with the genes of another, which forms the genetic traits of their offspring. While DNA and RNA are the primary pathways through which traits are inherited, a new study from the University of Toronto suggests its not the only pathway—and they came across this groundbreaking discovery by complete accident.
Brent Derry's lab at the University of Toronto led by Matthew Eroglu—now a postdoctoral research scientist at Columbia University—first began studying cancer signaling pathways using the hermaphroditic worm Caenorhabditis elegans. Surprisingly, over the course of the study the researchers noticed that the worms—which could be both male and female—became increasingly less fertile and more feminine over subsequent generations until eventually reaching complete sterilization. Intrigued by this epigenetic trait—changes that affect genes without altering the DNA sequence itself—Eroglu and his team kept digging and discovered the culprit: amyloids. The results were published in the journal Nature Cell Biology.
"There are a lot of traits and disorders that we know are passed on from parents to offspring if we look at family trees and so on,' Eroglu said in a press statement, 'but when people have done genome-wide association studies trying to link these traits to mutations or variants in genes, they frequently fall short of explaining all of the heritability that we see.'
One of the reasons could be epigenetic impacts such as these amyloids. Amyloids are extracellular proteins that, when built up in the body, can cause neurological diseases like Alzheimer's (though the amyloids in this study aren't exactly the same). When examining the increasingly feminizing worms, the authors noted that they contained 'autofluorescent green dots,' as the website El País describes. They called these dots 'herasomes,' and inside them were amyloid-like structures that are known to have the DNA-like ability to replicate themselves, making them possible inheritance vectors.
The researchers then performed a variety of tests, subjecting some worms to heat-induced stress while deactivating certain genes to test their hypothesis. These experiments only confirmed that amyloid structures in the herasomes are the cause behind this hyper-feminine (and eventual sterilization) phenomenon. Of course hermaphroditic worms are one thing, and humans traits are another, so future studies will need to investigate if similar pathways are possible in humans (though the authors suggest they don't see why they wouldn't).
'There's this alternate inheritance mechanism on top of DNA,' Eroglu said in a press statement. 'Could we discover something that, in fact, doesn't change sex but changes some other traits? Or predict diseases that we couldn't base on DNA alone?'
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