Changes in gene expression across body tissues as a function of diurnal variation in light and artificial light at night in the green anole Lizard

Most organisms detect and respond to light through opsin proteins, present in both ocular and extraocular tissues. Diurnal patterns of photoperiod are predictable in the natural world, but the widespread use of artificial light at night, especially in urban environments, has altered the patterns of light exposure for many organisms. To determine how artificial nocturnal light influences the diurnal expression of opsins and other genes, we used RNAseq in green anole lizards (Anolis carolinensis; both sexes) to measure gene expression across diverse tissue types. In the laboratory, we sampled brain, eye, skin, gonad, and liver tissues of anoles at midday in full spectrum light, midnight in full darkness, and midnight with exposure to artificial light and transcriptomics was performed. Our initial analyses indicate that opsin expression patterns differ among tissue types, but not as a function of time or day or light exposure. We have found that overall gene expression varies in the brain between midday and midnight, and there is highly variable expression in anoles that have been exposed to artificial light at night. Together our findings highlight the importance of understanding the effects of light pollution on wild, free living, anoles as well as the complexities of light detection and its response across anole tissues.