Fasick J I, Cronin T W, Hunt D M, Robinson P R
The Department of Biological Sciences, University of Maryland Baltimore County, Baltimore 21250, USA.
Vis Neurosci. 1998 Jul-Aug;15(4):643-51. doi: 10.1017/s0952523898154056.
To assess the dolphin's capacity for color vision and determine the absorption maxima of the dolphin visual pigments, we have cloned and expressed the dolphin opsin genes. On the basis of sequence homology with other mammalian opsins, a dolphin rod and long-wavelength sensitive (LWS) cone opsin cDNAs were identified. Both dolphin opsin cDNAs were expressed in mammalian COS-7 cells. The resulting proteins were reconstituted with the chromophore 11-cis-retinal resulting in functional pigments with absorption maxima (lambdamax) of 488 and 524 nm for the rod and cone pigments respectively. These lambdamax values are considerably blue shifted compared to those of many terrestrial mammals. Although the dolphin possesses a gene homologous to other mammalian short-wavelength sensitive (SWS) opsins, it is not expressed in vivo and has accumulated a number of deletions, including a frame-shift mutation at nucleotide position 31. The dolphin therefore lacks the common dichromatic form of color vision typical of most terrestrial mammals.
为了评估海豚的色觉能力并确定海豚视觉色素的最大吸收波长，我们克隆并表达了海豚视蛋白基因。基于与其他哺乳动物视蛋白的序列同源性，鉴定出海豚的视杆和长波长敏感（LWS）视锥视蛋白cDNA。两种海豚视蛋白cDNA均在哺乳动物COS-7细胞中表达。将所得蛋白质与发色团11-顺式视黄醛重组，产生功能性色素，视杆和视锥色素的最大吸收波长（λmax）分别为488和524nm。与许多陆地哺乳动物相比，这些λmax值有明显的蓝移。尽管海豚拥有与其他哺乳动物短波长敏感（SWS）视蛋白同源的基因，但它在体内不表达，并且积累了许多缺失，包括核苷酸位置31处的移码突变。因此，海豚缺乏大多数陆地哺乳动物典型的常见二色性色觉形式。
