Further, these results may have an implication for snail evolution and speciation - given that left- and rightward-coiling snails probably wouldn't interbreed." (we now have 5th-generation leftward-coiling snails). According to Kuroda: "It is remarkable that these snails with reversed coiling are healthy and fertile, and that this coiling can be inherited generation after generation Moreover, the mutant snails could be reared to adults, when they produced exclusively leftward-coiling Stage of development - when the snail embryo was just a single cell. Surprisingly, the researchers could see signs of asymmetry at the earliest possible Relocated to Chubu University, Japan), have now made snails with mutations in a gene called Lsdia1, which had previously been suggested - but not conclusively proven - to be involved in snail shell coiling snails without a functional copy of Lsdia1 produce offspring with shells that coil to the left, showing that this single gene is responsible for rightwardcoiling. Successfully applying CRISPR gene editing technology to molluscs for the first time, Masanori Abe and Reiko Kuroda (working at Tokyo University of Science, but recently But how does thisĪsymmetry come about? Researchers from Japan, writing in the journal Development, think they now have a definitive answer - for one species of freshwater snail (Lymnaea stagnalis) at least. This chirality (direction of coiling) of snail shells is an outward manifestation of left-right asymmetry: a phenomenon seen across animal evolution and extending to humans - your heart is (probably) on your left side, while your liver is to the right. Lefty snail will remember, these snails struggle to mate with the more common rightward-coiling individuals. But, occasionally, you might find an unlucky one that twists in the opposite direction - as fans of Jeremy the If you look at a snail's shell, the chances are it will coil to the right. view moreĬredit: Dr Hiromi Takahashi of the Kuroda laboratory. In contrast to the wild-type dextral snail (right), a CRISPR-created snail shows sinistral coiling (left).
Image: Knocking out one gene in the snail Lymnaea stagnalis reverses shell coiling.
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