Collective Behaviour - Winter Seminar Series 2021/22
There are other fish in the sea: Social density encoding by the neuropeptide Pth2
Speaker:
Lukas Anneser
There are other fish in the sea: Social density encoding by the neuropeptide Pth2
While sociality is a widespread feature among animals, its genetic underpinnings are only partially understood. In an unbiased sequencing screen in zebrafish, we identified the expression of the neuropeptide parathyroid hormone 2 (pth2) to be strongly upregulated by the presence of conspecifics. Pth2 transcript levels exhibit extremely rapid temporal dynamics. Within 30 minutes of exposure to conspecifics, previously isolated zebrafish showed a significant increase of pth2 transcript levels. The link between pth2 expression and the social environment is not developmentally restricted - the acute isolation of socially reared adult fish resulted in a rapid decrease in pth2 transcript levels. Furthermore, in socially reared fish the level of pth2 expression was tightly and positively correlated with the number of fish in the environment. In a series of experiments, we identified mechanosensation via the lateral line to be the modality with which the presence of conspecifics was perceived. We furthermore analyzed the molecular composition of the pth2 expression domain, which suggested that this area is homologous to the subparaventricular region in the mammalian thalamus. Ultimately, we subjected pth2 knockout fish to a battery of behavioral tests and found mutants to display signs of increased anxiety and impaired social behavior. The data presented suggests that the neuropeptide pth2 is part of a conserved system that enables the animal to react appropriately in different social contexts.
Datum: 2021-10-01