The Adaptive Evolution Of Vision Genes In Owls

Owls are the typically nocturnal birds with enhanced scotopic vision,while the underlying molecular basis of their dim-light vision remains largely unknown.In this study,we performed a comparatively evolutionary analyses of vision genes between owls and their diurnal relatives based on the retinal transcriptome sequencing.Our results showed that positive selection signal was detected in three dim-light vision genes,CNGA1,CNGB1 and SLC24A1,suggesting these genes may play an important role in enhancing their dim-light vision.Moreover,colour vision genes Sws2,Rh2,Lws along the ancestral branch of owls showed positive selection singal and 11 positively selected sites of SWS2 were identified,including 42 R,43A,126 G,67T,176 R,183R,184 A,202A,214 P,225A and 250 R,similarly,5 positively selected sites of Lws including 150 K,154K,161 L,168C and 281 N,were identified.The positive selection found in color vison genes would suggest colour vision is more likely important for owls.We were not capable of detecting the transcript of Sws1,which may suggest Sws1 may have become pseudogenes.This study would help us to understand the molecular basis underlying the great dim-light vision of owls.