Visual pigments of marine carnivores: pinnipeds, polar bear, and sea otter.

Rod and cone visual pigments of 11 marine carnivores were evaluated. Rod, middle/long-wavelength sensitive (M/L) cone, and short-wavelength sensitive (S) cone opsin (if present) sequences were obtained from retinal mRNA. Spectral sensitivity was inferred through evaluation of known spectral tuning residues.

Polymorphic New World monkeys with more than three M/L cone types.

Most New World (platyrrhine) monkeys have M/L cone photopigment polymorphisms that map directly into individual variations in visual sensitivity and color vision. We used electroretinogram flicker photometry to examine M/L cone photopigments in the New World monkey Callicebus moloch (the dusky Titi). Like other New World monkeys, this species has an M/L cone photopigment polymorphism that reflects the presence of X-chromosome opsin gene alleles.

Diurnality and cone photopigment polymorphism in strepsirrhines: examination of linkage in Lemur catta.

Trichromatic color vision is routine among catarrhine primates, but occurs only as a variant form of color vision in some individuals in most platyrrhine genera. This arises from a fundamental difference in the organization of X-chromosome cone opsin genes in these two lineages: catarrhines have two opsin genes specifying middle- and long-wavelength-sensitive cone pigments, while platyrrhines have only a single gene. Some female platyrrhine monkeys achieve trichromacy because of a species polymorphism that allows the possibility of different opsin gene alleles on the two X-chromosomes.

Cone pigment variations in four genera of new world monkeys.

Previous research revealed significant individual variations in opsin genes and cone photopigments in several species of platyrrhine (New World) monkeys and showed that these in turn can yield significant variations in color vision. To extend the understanding of the nature of color vision in New World monkeys, electroretinogram flicker photometry was used to obtain spectral sensitivity measurements from representatives of four platyrrhine genera (Cebus, Leontopithecus, Saguinus, Pithecia). Animals from each genus were found to be polymorphic for middle to long-wavelength (M/L) sensitive cones.

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.

Spectral sensitivity and photopigments of a nocturnal prosimian, the bushbaby (Otolemur crassicaudatus).

Earlier studies yielded conflicting conclusions on the types of photoreceptors and photopigments found in the eyes of nocturnal prosimians. In this investigation a noninvasive electrophysiological procedure, electroretinogram flicker photometry, was employed to measure scotopic and photopic spectral sensitivity in the thick-tailed bushbaby (Otolemur crassicaudatus). The scotopic spectral sensitivity function of the bushbaby has a peak of about 507 nm.

Photopigments underlying color vision in ringtail lemurs (Lemur catta) and brown lemurs (Eulemur fulvus).

A recent examination of color vision in the ringtail lemur produced evidence that these prosimians could make color discriminations consistent with a diagnosis of trichromatic color vision. However, it was unclear if this behavior reflected the presence of three classes of cone or whether lemurs might be able to utilize signals from rods in conjunction with those from only two classes of cone. To resolve that issue, spectral sensitivity functions were obtained from ringtail lemurs (Lemur catta) and brown lemurs (Eulemur fulvus) using a noninvasive electrophysiological procedure, electroretinographic flicker photometry.