Opsin gene and photopigment polymorphism in a prosimian primate

A recent genetic investigation found some species of prosimian to have an opsin gene polymorphism [Nature 402 (1999) 36]. In the present Study the functional implications of this finding were explored in a correlated investigation of opsin genes and spectral sensitivity measurements of a diurnal prosimian, Coquerel's sifaka (Propithecus verreauxi coquereli). Spectra recorded using electroretinogram (ERG) flicker photometry reveal a cone photopigment polymorphism paralleling an opsin gene polymorphism detected by molecular methods. This species has two middle-to-long-wavelength cone pigments with peak sensitivities of about 545 and 558 nm and a short-wavelength-sensitive cone with a peak at about 430 nm. The distribution of these pigments among animals predicts the presence of both dichromatic and trichromatic forms of color vision. (C) 2002 Elsevier Science Ltd. All rights reserved.