[Jim] Anderson is standing in an unassuming patch of woodland in Crystal Falls, in Michigan's Upper Peninsula. He is revisiting an organism living under the forest floor that he and his colleagues discovered nearly 30 years ago. This is the home of Armillaria gallica, a type of honey mushroom. When Anderson and his colleagues visited Crystal Falls in the late 1980s, they discovered that what at first appeared to be a rich community of Armillaria gallica flourishing beneath the mulch of leaf litter and top soil of the forest floor was in fact " one giant individual specimen. They estimated it covered an area about 91 acres, weighed 100 tonnes and was at least 1,500 years old. Analysis produced [a] surprising insight, one that could help us humans in our fight against ... cancer. The Canadian researchers discovered what may be the secret behind the Armillaria gallica's extraordinary size and age. It appears the fungus has an extremely low mutation rate " meaning it avoids potentially damaging alterations to its genetic code. As organisms grow, their cells divide into two to produce new daughter cells. Over time, the DNA in the cells can become damaged leading to errors, known as mutations, creeping into the genetic code. This is thought to be one of the key mechanisms that causes aging. But it seems the Armillaria gallica in Crystal Falls might have some inbuilt resistance to this DNA damage.