Scientists Edit Genes to Save Chestnuts and Endangered Species

A century ago, four billion American chestnut trees stretched across the Eastern United States in forests so dense that squirrels could travel from Maine to Georgia without touching the ground. Then a single fungus changed everything.

By the 1950s, chestnut blight had killed 99 percent of these towering trees. Today they're considered functionally extinct, reduced to roots and shoots struggling to survive.

Now scientists have a plan to bring them back. Using synthetic biology, researchers are editing the trees' DNA to make them resistant to the killer fungus that nearly erased them from existence.

"Synthetic biology opens up possibilities that really haven't existed until now to address this problem," says Andrew Newhouse, director of the American Chestnut Research and Restoration Project at SUNY. The approach works by tweaking an organism's genes to help it fight disease, survive climate change, or thrive in degraded environments.

The chestnut project is just the beginning. Researchers are testing heat-resistant genes in coral reefs to help them survive warming oceans. Others are developing a genetic vaccine for black-footed ferrets to protect them from sylvatic plague, a disease that's devastated their populations.

Some teams are even engineering plants to absorb heavy metals from polluted soil, cleaning up the damaged habitats where endangered species live. The technology borrows tools long used in agriculture and medicine but applies them to conservation for the first time.

The approach sparked debate at the World Conservation Congress last October. Some scientists worry about releasing gene-edited organisms into the wild without knowing how they'll affect ecosystems. Critics called for a moratorium, arguing the outcomes are too uncertain and potentially irreversible.

But supporters say rigorous testing, regulatory approval, and community consultation will happen before any releases. "There are checks and balances in place," says entomologist Krystal Birungi, who works on gene-edited mosquitoes. "People don't just go out there creating things by themselves, with no one having any oversight."

The Bright Side

Conservation leaders ultimately rejected the moratorium, choosing instead to adopt a framework governing how synthetic biology research moves forward. That means experiments can continue under careful supervision.

For native species like the American chestnut, the stakes are high. Hybrids exist, but planting fully native trees matters for ecological restoration. The gene-edited version could finally give these iconic trees the fighting chance they need.

After a hundred years of failed attempts to save the chestnuts, scientists finally have tools that might actually work. The same technology could help dozens of other species hanging on by a thread.