Absence of functional short-wavelength sensitive cone pigments in hamsters (Mesocricetus).
Studies of Syrian golden hamsters (Mesocricetus auratus) have yielded contradictory evidence as to whether the retina of this species supports a population of cones containing short-wavelength sensitive pigments. We undertook a re-examination of this issue by (a) measuring lens transmission, (b) determining complete spectral sensitivity functions using electroretinogram (ERG) flicker photometry, (c) employing a sensitive chromatic-adaptation paradigm in conjunction with ERG measurements to conduct a specific search for the presence of a short-wavelength sensitive mechanism, and (d) assaying for the presence of retinal mRNA using real-time, reverse transcription polymerase chain reactions (RT-PCR). Parallel measurements were made on Turkish hamster (Mesocricetus brandtii) and control measurements were derived from recordings made on a rodent whose retina is known to contain a population of short-wavelength sensitive cones (the rat, Rattus norvegicus). Although UV opsin transcripts can be detected in the retina of the Syrian hamster, the electrophysiological measurements imply that these are not translated. Syrian hamsters thus lack a functional short-wavelength sensitive pigment, and that seems also true for the Turkish hamster. Members of this genus belong to a disparate group of mammals that have lost function of their short-wavelength sensitive cone pigments through ancestral opsin gene mutations.
Williams
Gary A
GA
Neuroscience Research Institute and Department of Psychology, University of California, Santa Barbara, CA 93106, USA.
Jacobs
Gerald H
GH
D000818:Animals; D003118:Color Perception / Q000502:physiology*; D006224:Cricetinae; D004596:Electroretinography; D015870:Gene Expression; D008647:Mesocricetus / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D011846:Radio Waves; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017299:Rod Opsins / Q000096:biosynthesis*; D014466:Ultraviolet Rays; D014785:Vision, Ocular
D012333:RNA, Messenger; D017299:Rod Opsins