DNA research reveals how snakes invaded Guam

Invasive species often face a 'genetic bottleneck' when a small group colonizes a new area, which typically limits their survival.

However, the brown tree snake in Guam has defied this rule, reaching densities of up to 30,000 snakes per square mile since arriving as cargo stowaways after World War II.

By using advanced DNA sequencing, researchers identified over 19,000 'structural variants'—large-scale changes in their genetic code.

This discovery explains how the population became so resilient despite its limited starting numbers.

The invasion has been devastating for native wildlife, causing the extinction of many birds and lizards.

While the ecological damage is clear, this research provides a breakthrough in understanding the 'invasion paradox.'

It shows that structural genetic variation can act as a powerful engine for adaptation, allowing invasive species to bypass traditional evolutionary roadblocks.