Your Spiral or Mine? Snail gene reverses coil, makes new species

A snail with a shell spiraling to the right can’t mate readily with a lefty. So, changes in the single gene that controls shell direction have created new snail species, say researchers.

MATE BARRIERS. One gene determines which way these three Euhadra species coil. The lefty is E. quaesita (left) and the two righties are E.