What can a 2,500-year-old fungus teach us about genetics? Plenty, according to Johann Bruhn, a forest health specialist at the University of Missouri in Columbia, who has been collecting samples from a specimen spanning nearly 200 acres in a forest of Michigan’s Upper Peninsula.
The motivation for the study goes back 35 years, when Bruhn first planted some red pines that began to die prematurely. A virulent species of parasitic honey mushroom, Armillaria gallica, appeared to be the culprit. Further investigation of the fungus suggested that one specimen in particular, dubbed C1, appeared to extend far into the forest.
With the help of a team of researchers, Bruhn spent the better part of the next decade collecting hundreds upon hundreds of samples. By 1992, C1 weighed in at about 11 tons and, based on observed growth rates, appeared to date back 1,500 years.
The advent of whole-genome sequencing in recent years has made it possible to identify individuals with molecular markers. While a number of separate specimens were identified in close proximity to one another, a single individual—the mighty C1—coated hundreds of tree root systems spanning more than 75 hectares. The researchers revised their estimates, multiplying the mass of the fungus by four and adding another thousand years to its age.
The study, , concludes “that C1 was among the largest and oldest organisms on earth, a remarkable claim given that Armillaria is essentially a microorganism existing largely as microscopic hyphae embedded in their substrates.”
What’s the secret to C1’s longevity and size? A sequence of the genome from collected samples revealed an alarmingly low rate of mutation. In comparison to cancers, which are radically unstable genetically and exhibit exceedingly high rates of mutation, the fungus represents what Bruhn calls “.”
If there’s anything we can learn about genetic resilience from a parasitic mushroom that sprouted from a single sexual event 2,500 years ago, let’s get busy learning it already. There’s a good chance it could offer new insights into why cancer genomes are so unstable, and what we might do to stabilize them.
Humongous Fungus, show us the way.