Tiny Group of Snakes Conquered an Entire Island
A small population of brown tree snakes, introduced to Guam after World War II, has completely overrun the island, wiping out native forest birds and causing power outages. Researchers from the University at Buffalo and the U.S. Geological Survey have identified over 19,000 structural DNA variants that explain the snakes' survival under inbreeding conditions.
A small population of brown tree snakes, accidentally introduced to Guam after World War II, has completely overrun the island, dealing a devastating blow to the local ecosystem. The reptiles have nearly wiped out native forest bird populations and regularly caused widespread power outages by climbing onto high-voltage poles. At the peak of the invasion, population density in some areas reached thirty thousand individuals per two and a half square kilometers. For a long time, zoologists could not understand how a tiny group of reptiles managed to survive extreme inbreeding and take over the entire territory. A joint team of researchers from the University at Buffalo and the U.S. Geological Survey used long-read DNA sequencing and discovered more than nineteen thousand structural variants—large-scale changes where entire DNA fragments are duplicated, deleted, or moved. A significant portion of these variations was concentrated in genes responsible for the immune system and olfaction. Acute smell also played a role in preventing cannibalism, allowing snakes to recognize relatives. These findings challenge current views on the survival of inbred populations and open new prospects for conservation programs.