A novel mechanism for left-right asymmetry establishment involving tissue remodeling and MyoID

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. ### Competing Interest Statement The authors have declared no competing interest.