为什么多数蜗牛（螺）壳的螺旋多数是右旋的？估计大家都发现，蜗牛壳外的纹路绝大多数都是右旋的,小时候就一直想找一个左旋的，但是至今也没有找到，呵呵。对于（螺）壳上的螺旋为什么是右旋的，科学家们也一直不知道这是什么原因。最近，研究者发现了可使静水椎实螺壳外的螺纹右旋的基因Lsdia1，该基因被认为是参与了蜗牛（或螺）螺旋的形成。

科学家利用最近非常流行的CRISPR基因编辑技术成功的对Lsdia1进行了基因编辑，结果显示这些腹足类动物螺壳上的螺旋由右旋变为左旋，相关研究结果发表在2019年5月14日出版的Development期刊上（The development of CRISPR for a mollusc establishes the formin Lsdia1 as the long-sought gene for snail dextral/sinistral coiling），Science杂志对该有趣的实验结果进行了报道。Lsdia1 究竟是如何控制螺纹的形成还不是很清楚，科学家认为该基因可能编码特殊的控制内骨骼形成的蛋白质。

Most snail shells coil to the right. This single gene may be the reason why！

If you ever come across a group of snails, chances are most of their shells coil to the right. Until recently, scientists didn’t know why this was the case. Now, researchers have found the gene that makes this right-coiling happen in freshwater snails (Lymnaea stagnalis). 

For the first time, scientists used CRISPR, a tool that edits genes, successfully in snails. They mutated a gene called Lsdia1, which had been suggested in previous studies to be involved in shell coiling. Gastropods without a functional version of the gene produced offspring with shells that coiled to the left (pictured), researchers report today in the journal Development. These changes in shell coiling could be seen as early as the embryo stage.

It’s still not clear how Lsdia1 controls shell coiling all by itself. Scientists think it may encode a special protein that is involved in regulating cells’ internal skeleton, but more tests still need to be done.