Editors' ChoiceNeuroscience

Fruit Flies, Mosquitoes, and CO2 Sensations

Sci. Signal.  04 Mar 2008:
Vol. 1, Issue 9, pp. ec85
DOI: 10.1126/stke.19ec85

Many insects have neurons dedicated to CO2 sensation. The fruit fly Drosophila is repelled by CO2 and has its sensing neurons on its antennae. Mosquitoes, however, are attracted to CO2 and have their sensing neurons on their maxillary palps. Cayirlioglu et al. found that mutating a microRNA in the Drosophila genome produces a new class of CO2-sensing neurons on the maxillary palps. These olfactory receptor neurons also express two odorant receptors that are normally expressed in the fruit fly palps, and they project both to normal palp target glomeruli and to the glomerulus, which receives projections from the CO2 neurons in the antennae. Thus, the anatomy of the fruit fly CO2-sensing system is switched to an arrangement that resembles a hybrid between the fruit fly and the mosquito.

P. Cayirlioglu, I. G. Kadow, X. Zhan, K. Okamura, G. S. B. Suh, D. Gunning, E. C. Lai, S. L. Zipursky, Hybrid neurons in a microRNA mutant are putative evolutionary intermediates in insect CO2 sensory systems. Science 319, 1256-1260 (2008). [Abstract] [Full Text]