Choanoflagellate: Monosiga brevicollis (image) University of Texas at Austin Share Print E-Mail Caption University of Texas at Austin researchers discovered the genes for sodium channels that occur in animal neurons in the single-celled choanoflagellate, Monosiga brevicollis, showing that the sodium channels evolved before neurons. Credit Mark J. Dayel, University of California, Berkeley. Usage Restrictions Creative Commons. Credit: Mark Dayel. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.