The origin of vertebrate gills

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Current Biology 27 (2017): 729-732, doi:10.1016/j.cub.2017.01.022.Pharyngeal gills are a fundamental feature of the vertebrate body plan. However, the evolutionary history of vertebrate gills has been the subject of a long-standing controversy. It is thought that gills evolved independently in cyclostomes (jawless vertebrates—lampreys and hagfish) and gnathostomes (jawed vertebrates—cartilaginous and bony fishes), based on their distinct embryonic origins: the gills of cyclostomes derive from endoderm, while gnathostome gills were classically thought to derive from ectoderm. Here, we demonstrate by cell lineage tracing that the gills of a cartilaginous fish, the little skate (Leucoraja erinacea), are in fact endodermally derived. This finding supports the homology of gills in cyclostomes and gnathostomes, and a single origin of pharyngeal gills prior to the divergence of these two ancient vertebrate lineages.This research was supported by a Royal Society University Research Fellowship ( UF130182 ) and a grant from the University of Cambridge Isaac Newton Trust ( 14.23z ) to J.A.G. O.R.A.T. was supported by the Wellcome Trust (PhD studentship 109147/Z/15/Z) and the Cambridge Commonwealth Trust