title: Retinal transcriptome sequencing sheds light on the adaptation to nocturnal and diurnal lifestyles in raptors.
abstract: Owls (Strigiformes) represent a fascinating group of birds that are the ecological night-time counterparts to diurnal raptors (Accipitriformes). The nocturnality of owls, unusual within birds, has favored an exceptional visual system that is highly tuned for hunting at night, yet the molecular basis for this adaptation is lacking. Here, using a comparative evolutionary analysis of 120 vision genes obtained by retinal transcriptome sequencing, we found strong positive selection for low-light vision genes in owls, which contributes to their remarkable nocturnal vision. Not surprisingly, we detected gene loss of the violet/ultraviolet-sensitive opsin (SWS1) in all owls we studied, but two other color vision genes, the red-sensitive LWS and the blue-sensitive SWS2, were found to be under strong positive selection, which may be linked to the spectral tunings of these genes toward maximizing photon absorption in crepuscular conditions. We also detected the only other positively selected genes associated with motion detection in falcons and positively selected genes associated with bright-light vision and eye protection in other diurnal raptors (Accipitriformes). Our results suggest the adaptive evolution of vision genes reflect differentiated activity time and distinct hunting behaviors.
authors.affiliation: Jilin Provincial Engineering Laboratory of Avian Ecology and Conservation Genetics, Northeast Normal University, 5268 Renmin Street, Changchun, 130024, China.
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305-5020, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Hadly
authors.affiliation: Biomarker Technologies Corporation, Beijing 101300, China.
authors.forename: Wenjia
authors.initials: W
authors.lastname: Teng
authors.affiliation: Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun 130117, China.|Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, 5268 Renmin Street, Changchun, 130024, China.
authors.forename: Yuyang
authors.initials: Y
authors.lastname: Hao
authors.affiliation: Ministry of Education Key Laboratory for Tropical Animal and Plant Ecology, College of Life Sciences, Hainan Normal University, Haikou 571158, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liang
authors.affiliation: Jilin Provincial Engineering Laboratory of Avian Ecology and Conservation Genetics, Northeast Normal University, 5268 Renmin Street, Changchun, 130024, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Jilin Provincial Engineering Laboratory of Avian Ecology and Conservation Genetics, Northeast Normal University, 5268 Renmin Street, Changchun, 130024, China.
authors.forename: Haitao
authors.initials: H
authors.lastname: Wang