Butterfly lilies in the genus Wachendorfia occur as left- and right-handed floral morphs. A peer-reviewed Science paper published on 30 July 2026 shows that this dimorphic enantiostyly is produced by a combination of genetically controlled chirality and gravitropism.
Opposite morphs place pollen on different parts of pollinators
The style and the functionally important stamen deflect to opposite sides. Left- and right-handed flowers therefore place and receive pollen from corresponding positions on a pollinator’s body, reducing sexual interference and promoting cross-pollination between morphs.
A hemizygous supergene coordinates female and male orientation
The right-handed morph carries an R locus that behaves as a hemizygous supergene. Two major candidate causal loci are MIR156-R, associated with female-organ orientation, and YUCCA-R (YUC-R), associated with the opposite orientation of the male organ. Natural deletions, expression patterns and auxin measurements support this division of roles.
Because stable transformation is not established in Wachendorfia, this is not a simple knockout-proof study; the causal inference comes from converging genetic, expression, developmental and natural-variant evidence.
Gravity supplies the external left-right reference
Inverting developing buds and reducing directional gravity cues with a clinostat showed that final organ deflection depends on gravitropism interacting with intrinsic chirality. The flower therefore uses gravity as an external reference axis rather than relying only on its internal dorsoventral geometry.
The Science version is now the canonical source
The earlier bioRxiv preprint has been superseded by the peer-reviewed Science version. The key advance is the integration of a supergene, developmental chirality, gravity and allele-specific pollen placement into one reproductive system.
For related context, see Morning Female, Later Male: SDMYB Underlies Avocado Flowering Type and an Ancient 44-Million-Year Polymorphism.
For related context, see The 4.83-Gb Ophrys sphegodes Genome Links Sexual Deception to Odor-Gene Duplications and an LTR Burst.
For related context, see OsMYB8 Controls When Rice Florets Open—A Tool for Synchronizing Indica × Japonica Hybrid Seed Production.
Reference
- Xue H et al. Supergene control of chiral development in mirror-image flowers. Science. 2026;393(6810):eaeb1157. https://doi.org/10.1126/science.aeb1157
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