Cited research: PloS Genet. doi:10.1371/journal.pgen.1000929 (2010)

Lizards on the Caribbean's Lesser Antilles islands were thought to provide a rare example of evolution resulting from geographical isolation. But work by Roger Thorpe and his colleagues at Bangor University, UK, suggests otherwise. They studied populations of the lizard Anolis roquet (pictured) on the island of Martinique. This island formed by the merging of four ancient islands, each of which had already been populated by its own lizard species for between six million and eight million years.

Using genetic analysis, the researchers found that lizards that originated on separate islands showed less reproductive isolation than populations from the same island that lived in distinct habitats. The results suggest that speciation was driven by adaptation to new habitats and not geographical isolation.

Credit: R. THORPE