Using the zebrafish, a model organism widely used in genetic studies, researchers have found that when it comes to social interactions with other fish, individual zebrafish learn to prefer one fish color pattern over another according to their early experience with these patterns. The work extends the utility of zebrafish to studies of behavior and evolution and is reported by University of Texas researchers Raymond E. Engeszer, Dr. David M. Parichy, and Dr. Michael J. Ryan.
Social behavior has long been of interest to biologists and psychologists alike. The studies reported this week suggest that the extensive knowledge of zebrafish genetics will afford researchers an opportunity to see how genes, development, and environment lead to behaviors that mediate social interactions.
The investigators examined the way fish choose their consorts during the formation of loose social aggregates, called shoals, and they exploited the developmental genetic resources of this biomedical model organism to manipulate the appearance of the fish. Fish were chosen to have drastically different color patterns, either blue and gold stripes or an absence of stripes and a uniform mother-of-pearl color. This difference was the result of a single DNA base change in the fish's genome. To determine whether genes or the environment determine individuals' preferences, the investigators raised subject fish either with other fish of their own color or with fish of the alternate color. When subject fish were later allowed to choose which color of fish to associate with, they greatly preferred whichever color pattern they had been raised with, irrespective of their own color. This learned social preference could have enormous impacts on the survival and reproductive success of individual fish. This work represents a first step in using the zebrafish and the tools of developmental genetics to investigate long-standing questions concerning the impact of behavior on evolution.
Raymond E. Engeszer, Michael J. Ryan, and David M. Parichy: "Learned Social Preference in Zebrafish"
Published in Current Biology, Volume 14, Number 10, May 25, 2004.