Yep, the humble snail has captivated scientists once more!! A genetic similarity has been found between snail living in Ireland and those living in southern Europe, such as southern France and northern Spain
This evidence gives further weight to the fact that the population of Ireland may have originated from settlers who migrated from places other than Britain. The snails are thought to have been carried by the French on a boat, but whether or not the sailors had them as a snack (the French still eat snails, ew) or the snails just accidentally found themselves on the boat is unclear.
Other evidence that suggests the some Irish could have French/Spanish ancestry includes blood groups, the Y chromosomes, and also in some diseases.
The snail is not found in England, Scotland or Wales, which suggests that the immigrants knew they only wanted to settle in one place, or they perhaps just did not reach the UK.
More information about this can be found here: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0065792