Stone Age people may have carried land snails on a voyage from the Pyrenees to Ireland, an examination of the snails’ DNA reveals.
Scientists have struggled to explain why Ireland shares some plant and animal species with the Iberian Peninsula, but not with the rest of Europe or the British Isles. For example, Cepaea nemoralis land snails on Ireland’s western coast and in the southern Pyrenees share unique white-lipped shells.
To find out if the two populations of white-lipped snails are related, Angus Davison and Adele Grindon of the University of Nottingham in England took DNA samples from the species all over Europe. The researchers found that snails in Ireland and the Pyrenees share a variation in one gene that distinguishes them from other European specimens.
The simplest explanation, Davison and Grindon report June 19 in PLOS ONE, is that humans journeying to Ireland about 8,000 years ago brought along escargot as a food source. “Other explanations get quite convoluted,” Davison says.