Seasonal and daily ocular transcriptome of echolocating bat T. brasiliensis
There are many examples of animal sensory systems displaying transient optimizations to accommodate cyclical changes in the local environmental conditions. Seasonal fluctuations in visual perception are documented in many species, including humans, but the mechanisms and ecological significance of these adaptations often remain obscure. Although much less is known about their visual ecology than their hearing, the diversity of bat species makes this group a useful model for studying sensory adaptation mechanisms. Here we analyze daily and seasonal changes in gene expression in the eyes of a temperate echolocating bat, the Mexican free-tailed bat (Tadarida brasiliensis). A total of 44 wild-caught bats were sampled at different time points from the same location across all four seasons, with whole eyes sequenced for total mRNA expression. Overall expression patterns were analyzed using differential expression analysis and additional clustering techniques for identifying correlation networks and evidence of cyclical enrichment. Additionally, a target gene list representing key physiological processes was applied to assess which biological pathways displayed the most robust seasonal or daily changes. 17.8% of genes showed significant differential expression based on season, compared to 11.5% of genes based on daily expression. Several gene networks related to the circadian clock, phototransduction, and metabolic function displayed significant rhythmic seasonal effects. Thus, the ocular transcriptome exhibits seasonal remodeling with signals consistent with retinal phototransduction, suggesting a potential role for vision in summertime.
There are many examples of animal sensory systems displaying transient optimizations to accommodate cyclical changes in the local environmental conditions. Seasonal fluctuations in visual perception are documented in many species, including humans, but the mechanisms and ecological significance of these adaptations often remain obscure. Although much less is known about their visual ecology than their hearing, the diversity of bat species makes this group a useful model for studying sensory adaptation mechanisms. Here we analyze daily and seasonal changes in gene expression in the eyes of a temperate echolocating bat, the Mexican free-tailed bat (Tadarida brasiliensis). A total of 44 wild-caught bats were sampled at different time points from the same location across all four seasons, with whole eyes sequenced for total mRNA expression. Overall expression patterns were analyzed using differential expression analysis and additional clustering techniques for identifying correlation networks and evidence of cyclical enrichment. Additionally, a target gene list representing key physiological processes was applied to assess which biological pathways displayed the most robust seasonal or daily changes. 17.8% of genes showed significant differential expression based on season, compared to 11.5% of genes based on daily expression. Several gene networks related to the circadian clock, phototransduction, and metabolic function displayed significant rhythmic seasonal effects. Thus, the ocular transcriptome exhibits seasonal remodeling with signals consistent with retinal phototransduction, suggesting a potential role for vision in summertime.
Texas A&M University