Eyespot Development on Butterfly Wings: The Focal Signal

摘要: Abstract The eyespot colour pattern on butterfly wings is specified in the early pupal epidermis by signals from a central "focus." In Bicyclus anynana we show that small square of focal epidermis, grafted to range distal wing sites, induces formation surrounding host tissue. Signaling limited focus, and even an adjacent (parafocal) graft does not maintain its normal fate (of contributing eyespot) influence surroundings. Along wing, there abrupt change as focus proximal site provokes no response. results several grafting experiments demonstrate their different response properties are autonomous areas nonresponding tissue can nonetheless transmit signal. dorsal forewing has anterior large posterior eyespot, this mainly difference signals, epidermal A whereas Furthermore, eyespots differ proportions, also depends identity responding epidermis. Eyespots over many cell diameters mechanism which could consist one long-range signal, such morphogen gradient or cascade short-range interactions initiated focus. Focal control size proportion between more readily compatible with mechanism. Neither model, however, explains why induced smaller, but peripheral gold annulus broader than corresponding eyespot. Also, direct evidence for gradients, any other insect epithelium.