Genetic control of collective behavior in zebrafish

Many animals, including humans, have evolved to live and move in
groups. In humans, disrupted social interactions are a
fundamental feature of many psychiatric disorders.  However, we
know little about how genes regulate social behavior.  Zebrafish
may serve as a powerful model to explore this question.  By
comparing the behavior of wild-type fish to 90 genetic lines, we show that
mutations of genes associated with human psychiatric disorders can alter
the collective behavior of adult zebrafish.  We identify three
categories of behavioral variation across mutants: "scattered",
in which fish show reduced cohesion; "coordinated", in which
fish swim more in aligned schools; and "huddled", in which fish
form dense but disordered groups. Changes in individual interaction rules
can explain these differences.  This work demonstrates how
emergent patterns in animal groups can be altered by genetic changes in
individuals, and establishes a framework for understanding the
fundamentals of social information processing.