Worms can inherit a ‘memory of longevity’ from long-lived parents
Long-lived worms can transmit their extended lifespan to the next generation by passing on changes in the way their genes are used, rather than differences in DNA itself.
A study has shown that nematode worms can inherit a “memory of longevity” from their parents, even though their genome remains unchanged.
It is not clear if the same processes apply to humans, but Anne Brunet from Stanford University, who led the study, noted that some genes that affect the lifespan of nematodes were later found to influence human longevity too. “In several cases, the worm has proved to be a good model for humans, who live 2,000 times longer,” she said.
Her team is now looking to see if the results in the worm Caenorhabditis elegans translate to species that are evolutionarily closer to humans, such as fish and mice.
The discovery is an example of “epigenetic inheritance”, where organisms pass on changes in the way genes are used rather than in the genes themselves. As animals develop, their DNA and proteins become annotated by molecular marks that act like Post-It notes, dictating which genes are read without changing the underlying text. The marks are meant to be stripped away with each new generation, but some stay behind.
Brunet says her study and others show that epigenetic inheritance has broad implications for complex traits like longevity, or possibly even diseases like Alzheimer’s, cancer and diabetes. “These have very different causes, including genetic factors and what we do to ourselves. But maybe we’re missing a component: what our parents and grandparents have done,” she says.
Studies like this could help to improve techniques such as cloning or reprogramming cells to become stem cells, which depend on correctly erasing or maintaining epigenetic marks. Eventually, scientists may even be able to manipulate these marks to boost lifespan or reduce the risk of diseases that pass from one generation to the next.
The latest discovery, published on Wednesday in the journal Nature, began when Brunet’s student Eric Greer was working with worms that had mutations in one of three genes – ASH-2, WDR-5 and SET-2. This trio controls how DNA is packaged, converting it from a tightly packed form into a loose, open one where genes can be more easily read…