Snails of the Tudorella sulcata species, which lives on land, are found all around the Western Mediterranean: in France, Spain, Sardinia, Algeria and Malta. A new genetic study deals on how the snails, original from SW Europe, made it to Sardinia and Algeria.
Ruth Jesse et al. Phylogeography of a Land Snail Suggests Trans-Mediterranean Neolithic Transport. PLoS ONE 2011. Open access.
|Sampling sites (color-coded by region)|
|Statistical parsimony networks with based on 604 bp of the mitochondrial COI gene (a) and 219 bp of the nuclear hsp70 gene (b).|
As often happens, the haploid (not recombined) mitochondrial genome is the most informative: the snails traveled to Africa mostly via Sardinia.
The authors estimate (???) ages between 10 and 3,000 years ago, with a m.l. date of 8000 BP and claim this would have some sort of relation with Neolithic spread. However this is far from clear: on one side there is no known Sardinia-North Africa interaction before Megalithism (since c. 6-5000 years ago, dying out gradually only around 3000 years ago), which would also include Malta in the equation. On the other side, Iberia, a possible alternate origin/route has been neglected in the research.