2026-10-08 カリフォルニア大学サンディエゴ校（UCSD）
Antibody stains in a developing butterfly retina show that each unit eye contains two R7 color photoreceptors. Credit: Perry Lab, UC San Diego
＜関連情報＞
- https://today.ucsd.edu/story/the-story-behind-the-butterflys-enhanced-visual-world-of-color
- https://www.science.org/doi/10.1126/sciadv.aei7570
蝶の色覚における感覚受容体の拡張と神経調節 Sensory receptor expansion and neural accommodation in butterfly color vision
Ke Gao, Julia Ainsworth, Antoine Donati, Yunchong Zhao, […] , and Michael W. Perry
Science Advances Published:7 Oct 2026
DOI:https://doi.org/10.1126/sciadv.aei7570
Abstract
The evolution of complex brains required the incorporation of newly evolved neurons into existing circuits, yet the genetic and developmental mechanisms enabling their integration remain poorly understood. Butterflies expanded their color vision by adding a second R7 photoreceptor per ommatidium, a rare departure from the conserved insect eye ground plan. Because each R7 makes an independent stochastic fate choice, this duplication increased the number of ommatidial types from two to three. We identified the genetic basis of this expansion and demonstrated how the brain accommodates the new input. R7 duplication was achieved by converting R3/4 cells to an R1/6 fate, triggering the R7 recruitment program on both sides of the ommatidium. By manipulating transcription factor expression in Drosophila, we engineered a “butterfly-fly” that recapitulates this ancient R7 duplication and three-type stochastic mosaic. In the fly brain, two R7 subtypes connect to specific types of Dm8 neurons, which are born in excess and undergo apoptosis if they fail to find synaptic partners. In our butterfly-fly model, these surplus Dm8s are immediately rescued and form subtype-appropriate connections. These findings suggest that population-level variation maintains a reservoir of potentially interacting neurons, providing a developmental substrate that allows the brain to immediately accommodate newly evolved neurons.
