Evolution of a novel left-right asymmetry involving tissue remodelling and MyoID

Abstract

How novel left-right asymmetries evolve in animals is unknown. Drosophila pachea males display a unique left-right asymmetry in the genital organs and mate in a right-sided position onto the female. In flies, male genitalia undergo a clockwise 360° rotation during development. To test if this tissue remodeling process is linked to asymmetry development in the male genitalia of Drosophila pachea, we developed CRIPSR and transgenesis in this singular species. As in D. melanogaster, mutants of the MyoID gene homolog undergo reverse rotation of the developing genitalia. In addition, they have mirror-image asymmetric genitalia. Although their genital asymmetry is reversed mutants still adopt a right-sided copulation posture. Our results reveal a novel mechanism for establishing left-right asymmetry in animals, involving complex tissue remodeling and MyoID.