A research group headed by a University of Hawaii biologist has discovered some surprising similarities between blind, albino cave fish and humans who have autism and schizophrenia.
The findings are examined in a June 24 article in the journal Science.
Lead researcher Masato Yoshizawa, an assistant professor of biology at UH, has been studying the Mexican tetra cave fish, which lives in fresh water, for more than a decade.
The cave fish, which evolved with no eyes and no pigment, has a close relative in a similar tetra that lives near the surface. Unlike the surface fish, however, the cave fish does not assemble in schools, does not have a social structure and almost never sleeps.
The cave fish are also hyperactive and tend toward repetitive behavior. Compared with their surface relatives, they also seem to experience higher anxiety.
The cave fish appears well suited for the study of disorders like autism and schizophrenia. Whereas rodents tend not to respond to treatments designed to produce such disorders in them, the cave fish’s natural sleeplessness, hyperactivity and asocial behavior already align with common symptoms of the disorders.
More significantly, the cave fish have 90 percent of the 101 risk factor genes most commonly associated with human psychiatric disease.
As part of its investigations, the research team treated the fish with different psychiatric drugs and found that they responded much like humans do. For example, Yoshizawa found that Fluoxetine (Prozac) and Clozapine made the fish sleep more and swim less.
Yoshizawa presented his findings in June at the 23rd International Conference on Subterranean Biology in Fayetteville, Ark.
The study is ongoing, with future initiatives planned to identify specific genes associated with extremes of designated behaviors, and how those genes interact with each other and the environment.
Ultimately, the study could help researchers better understand human mental disorders and how to treat them.
Animals that live in lightless environments often evolve to lose their eyesight and pigment. These include blind, albino crickets found in lava tubes on Hawaii island.
