Genetic Basis For Behavior In Fish Found
September 12, 2013

Study Shows Genes Help Fish Stay In School

Brett Smith for – Your Universe Online

A new study on the schooling habits of fish could provide new insights into the social behaviors and natural variations of humans.

Published on Thursday in the journal Current Biology, the new study was able to trace the tendency and the aptitude for schooling to different genomic regions in the threespine stickleback, a small fish that lives in the Northern Hemisphere.

"The motivation to be social is common among fish and humans," said study Anna Greenwood, a human biology scientist at Fred Hutch Cancer Research Center. "Some of the same brain regions and neurological chemicals that control human social behavior are probably involved in fish social behavior as well."

Greenwood and her colleagues at Fred Hutch have been working with sticklebacks for several years to understand the basis of natural variation. Through previous research, the team found that a group of marine sticklebacks from the Pacific Ocean schooled strongly, while a group from a lake in British Columbia were less sociable and less able to maintain a schooling formation. Even when both groups were raised in a lab setting, they exhibited different behaviors when placed together in a schooling situation.

"That really suggests that there's some kind of genetic factor controlling this difference," Greenwood said.

Hans Hofmann, a professor of integrative biology at the University of Texas at Austin who was not involved in the study, said the research also rebuts the assertion that human behavior is too complex to understand.

"I think it shows that even such complex behaviors associated with other individuals in a very rigid and organized manner can be dissected genetically," he said. "Studies like this tell us that we might get there eventually."

In the new study, the researchers looked at the schooling behaviors of lab-raised hybrids derived from strongly-schooling, saltwater sticklebacks and the schooling-averse freshwater species. To get the lab-raised fish to school, researchers used a group of eight fake plastic fish suspended from a spinning bicycle wheel. The fake fish simulated schooling and thereby enticed the real fish to follow suit.

The experimental setup was fashioned from scratch and could be considered part scientific project and part found-object art sculpture.

"It was a few weeks of going around to shops," Greenwood said.

In addition to connecting specific schooling behaviors with genomic regions, the study also revealed that these same regions of the genome appear to affect both the stickleback's ability to school as well as the anatomy of its lateral line, a system of organs that sense movement and vibration in water. The lateral line also contains the same sensory hair cells found in the human ear.

Greenwood said the additional finding could mean that a single gene affects how fish detect their environment and supports the long-held idea that schooling behavior is controlled in part by the lateral line.

The Fred Hutch researchers are currently working on manipulating the lateral line gene to see if that alters the fishes' schooling behavior.

While studying fish behavior may seem like an odd choice for scientists at a cancer research center, Greenwood said natural variation research can lead to new insights on susceptibility to disease.

"If we can understand the process by which evolution works and the genes that tend to be affected during evolution in these other model systems, we can apply that to humans," she explained.