RESEARCH that has identified the genes responsible for color vision has revealed a strong connection among the myriad sensory genes, including those involved in transmitting the sense of smell, regulation of heart rate, processing memory, and thinking.
Jeremy Nathans, MD, PhD, assistant professor of molecular biology, embarked on this sensory trail at Stanford (Calif) University, where he and colleagues isolated the genes for three pigment proteins that function as receptors on the cone cells of the retina. The pigment proteins respond to light of different wavelengths to register the colors red, green, and blue.
In doing so, they took advantage of a previously isolated gene for bovine rhodopsin, the pigment in rod cells responsible for black-and-white vision. They theorized that the rhodopsin and the three color pigment genes had evolved from a common precursor and that there would be a relatively high degree of homology among the four genes. Thus,