Single-Cell Analysis of an Intrinsic Reversal of Phototactic Behavior in Tilapia Larvae

Even though the transition from protected early life stages to independent living represents one of the most critical developmental milestones in animal life histories the neural underpinnings of offspring behavioral adaptations to these transitions remain poorly understood.

Here, we used single-nucleus RNA sequencing of whole larval brains of the Nile Tilapia, Oreochromis niloticus, a maternal mouthbrooder, to uncover the neural maturation processes associated with the dramatic developmental reversal in phototactic behavior during the transition from buccal incubation to freely swimming fry. We found that the behavioral switch from negative to positive light preference is accompanied by global brain maturation and a widespread remodeling of cell-type-specific gene co-expression networks, including a dramatic down-regulation of neural hemoglobin.