New collaboration in Science

The paper "Bilateral visual projections exist in non-teleost bony fish and predate the emergence of tetrapods" from Alan Chédotal group has just been published in Science in collaboration with groups from France, Spain, USA and Australia.

The article explains that in most vertebrates, camera-style eyes contain retinal ganglion cell neurons that project to visual centers on both sides of the brain. However, in fish, ganglion cells were thought to innervate only the contralateral side, suggesting that bilateral visual projections appeared in tetrapods. Here we show that bilateral visual projections exist in non-teleost fishes and that the appearance of ipsilateral projections does not correlate with terrestrial transition or predatory behavior. We also report that the developmental program that specifies visual system laterality differs between fishes and mammals, as the Zic2 transcription factor, which specifies ipsilateral retinal ganglion cells in tetrapods, appears to be absent from fish ganglion cells. However, overexpression of human ZIC2 induces ipsilateral visual projections in zebrafish. Therefore, the existence of bilateral visual projections likely preceded the emergence of binocular vision in tetrapods.

Vigouroux RJ, Duroure K, Vougny J, Albadri S, Kozulin P, Herrera E, Nguyen-Ba-Charvet K, Braasch I, Suárez R, Del Bene F, Chédotal A. Bilateral visual projections exist in non-teleost bony fish and predate the emergence of tetrapods. Science. 2021 Apr 9;372(6538):150-156. doi: 10.1126/science.abe7790. PMID: 33833117.

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