Photoreceptor distribution in the retinas of subprimate mammals

Relevant data on the distribution of color cones are summarized, with speci al emphasis on the marked dorsoventral asymmetries observed in a number of mammalian species. In addition, an overview is given of studies that demons trate the coexistence of two visual pigments within the same cone cell. The biological significance of these phenomena is discussed in conjunction wit h comparative immunocytochemical analyses of subprimate retinas. Based on v arious cone distribution patterns and temporal and spatial visual pigment c oexpression, two models of cone photoreceptor differentiation are suggested . (C) 2000 Optical Society of America [S0740-3232(00)00703-1].