Experience: I helped a snail find love

It is difficult for lefty snails to mate with normal snails because they have genitals on the opposite side of their head

It began when a retired scientist at the Natural History Museum in London told me that he had found a rare garden snail with a left-coiling shell. In 20 years of researching the genetics of snails at universities around the world, I had never found a lefty" garden snail. My first thought was that this snail could be used to discover what makes most other snail shells coil clockwise. As with our previous work, in which we showed that snails and other animals may use the same genes to define left and right, perhaps the new snail might contribute to understanding human asymmetry. For example, we usually have our heart to the left, but rare individuals are reversed.

The problem was that it is very difficult for lefty snails to mate, because they not only have a reversed shell but also genitals on the opposite side of their head to normal snails. Imagine trying to shake hands with your right hand with someone who insists on using their left. It doesn't work. How could we understand the genetics if we could not get offspring from the lefty?