Evolutionary divergence of locomotion in two related vertebrate species
Gokul Rajan, Julie Lafaye, Giulia Faini, Martin Carbó-Tano, Karine Duroure, Dimitrii Tanese, Thomas Panier, Raphaël Candelier, Jörg Henninger, Ralf Britz, Benjamin Judkewitz, Christoph Gebhardt, Valentina Emiliani, Georges Debrégeas, Claire Wyart, Filippo Del Bene
Abstract
Locomotion exists in diverse forms in nature; however, little is known about how closely related species with similar neuronal circuitry can evolve different navigational strategies to explore their environments. Here, we investigate this question by comparing divergent swimming pattern in larval Danionella cerebrum (DC) and zebrafish (ZF). We show that DC displays long continuous swimming events when compared with the short burst-and-glide swimming in ZF. We reveal that mesencephalic locomotion maintenance neurons in the midbrain are sufficient to cause this increased swimming. Moreover, we propose that the availability of dissolved oxygen and timing of swim bladder inflation drive the observed differences in the swim pattern. Our findings uncover the neural substrate underlying the evolutionary divergence of locomotion and its adaptation to their environmental constraints.