Guam's brown tree snake invasion linked to hidden genetic diversity

Brown tree snakes, native to Australia and the South Pacific, arrived in Guam after World War II, likely hitching rides on military cargo. The invasive population has driven many native birds to local extinction and causes hundreds of power outages each year, with densities reaching up to 30,000 snakes per square mile.

A study led by the University at Buffalo and the U.S. Geological Survey, published in Science Advances, used long‑read genome sequencing to uncover thousands of structural variants in the snakes’ DNA, especially in genes related to immunity and smell. This hidden genetic diversity explains how the tiny founding population avoided the expected inbreeding bottleneck, adapted rapidly, and expanded dramatically across the island.

The findings suggest the invasion may be more resilient to control efforts than previously thought, while also offering insights that could aid conservation of endangered species with small, inbred populations.