title: Differentially-expressedopsingenes identified inSinocyclocheiluscavefish endemic to China.
abstract: Eye degeneration is a common troglomorphic character of cave-dwelling organisms. Comparing the morphology and molecular biology of cave species and their close surface relatives is a powerful tool for studying regressive eye evolution and other adaptive phenotypes. We compared two co-occurring and closely-related species of the fish genusSinocyclocheilus, which is endemic to China and includes both surface- and cave-dwelling species.Sinocyclocheilus tileihornes, a cave species, had smaller eyes thanSinocyclocheilus angustiporus, a surface species. Histological and immunohistochemical analyses revealed that the cavefish had shorter cones and more disorderly rods than did the surface-dwelling species. Using quantitative PCR andin situhybridization, we found thatrhodopsinand a long-wavelength sensitiveopsinhad significantly lower expression levels in the cavefish. Furthermore, one of two short-wavelength-sensitiveopsinswas expressed at significantly higher levels in the cavefish. Changes in the expression ofopsingenes may have played a role in the degeneration of cavefish eyes.
authors.affiliation: Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Fanwei
authors.initials: F
authors.lastname: Meng
authors.affiliation: Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Yahui
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA.
authors.forename: John H
authors.initials: JH
authors.lastname: Postlethwait
authors.affiliation: Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Chunguang
authors.initials: C
authors.lastname: Zhang
keywords: Cavefish; Eye; Opsin; Retina; Sinocyclocheilus