Using bioinformatics to identify putative ORs in the Photinus pyralis transcriptome
Author:Anqi Zang ’23
Faculty Mentor(s):Sarah Lower, Biology
Funding Source:Department of biology, National Science Foundation Grant
Animals use diverse signals to find mates. Some signals are simple, and are emitted in a single mode, for example, visual or acoustic; while others are really complex, with multiple signal components transmitted simultaneously or sequentially over different modes. When we think about fireflies, we usually immediately think of an image that shines like stars in the night. Fireflies, which fall under the Lampyridae family of insects in the Coleoptera order of beetles, produce a chemical reaction inside their bodies that allows them to light up and they mainly use this ability to find a mate. But in fact, contrary to popular belief, not all firefly species are bioluminescent as adults. The unlighted-adult fireflies are day-active, and females may attract males over long and short distances by pheromones. Pheromones are detected by the firefly’s odorant receptors (ORs), which are heteromultimeric ion channels consisting of an evolutionarily conserved odorant co-receptor (Orco) and a variable non-Orco. Together, they form an OR complex that facilitate odorant binding and signal transduction. Previous work in the lab using a conservative homology-based approach found 27 ORs, including Orco, in Photinus pyralis, which is a lighted species with the most continuous genome assembly in fireflies. However, ORs can be very divergent and thus, missed when searching using conservative parameters. This project sought to develop a more expansive search strategy for ORs using both homology and structure-based predictions. Using this strategy, we identified over 100 putative ORs in the P. pyralis genome. The results of this study will provide a basis for future studies on the expression and evolution of ORs in fireflies.