An ancient polymorphism in myosin I a/b determines chiral variation in Japanese Euhadra snails.

An ancient polymorphism in myosin I a/b is linked to chiral variation in Japanese Euhadra snails, with both gene variants being evolutionarily old and functionally distinct.

• Why it matters: Understanding LR asymmetry is crucial for developmental biology, but most animals show little variation, making Euhadra snails a valuable model for studying natural chiral diversity without pathology.
• What they did: Researchers analyzed genetic differences in Euhadra snails, identifying a polymorphism in an unconventional myosin I a/b gene that causes chiral variation, with minimal transcriptional differences in embryos.
• The result: The study suggests that amino acid substitutions in the myosin motor domain may influence actomyosin interactions, expanding knowledge of molecular mechanisms underlying LR symmetry breaking.