Visual System, Siamese Cats

Abstract

In Siamese cats, a genetic mutation at the albino locus, known for producing the characteristic Siamese coat color, also somehow causes an excessive number of ganglion cell axons from each retina to cross in the optic chiasm and travel to the wrong side of the brain. As a consequence, the central visual pathways of Siamese cats are abnormal; abnormalities are also found behaviorally and in eye movement control, since these animals demonstrate a marked Strabismus. Thus, the Siamese mutation provides a unique opportunity to study how the visual system responds to abnormal inputs from the two eyes. And because a gene rather than a scalpel is responsible, it should be possible to learn about some of the cellular and molecular events that control the routing of optic axons in mammals.