Moths, with their distinctive nighttime flights and pollination abilities, are shedding light on the evolution of species with different traits. A gene known as disco may be responsible for differences in flight patterns between two colorful moth species. A recent study published in the journal Proceedings of the Royal Society B: Biological Sciences on August 27 delves into how this gene could regulate day or night flight.
When species diverge
Speciation, the process by which one species splits into two or more over time, often occurs when populations become geographically isolated. The famous finches of the Galápagos Islands studied by Charles Darwin are a prime example of this phenomenon. In the case of some moths, genetic differences have been influenced by their preferred time of activity rather than physical barriers. The study focuses on two closely related moth species in the southeastern United States.
Rosy maple moths belong to the genus Dryocampa and exhibit vibrant pink and yellow colors. They are nocturnal flyers. In contrast, pink-striped oakworm moths of the genus Anisota have more subdued colors and are active during dusk and daytime.
The study found that differences in flight patterns between these moth species are tied to their clock genes, which regulate circadian rhythms. Clock genes control various biological processes beyond sleep cycles, impacting cell growth, blood pressure, body temperature, and metabolism.
Genes that ‘tell time’
Clock genes play a crucial role in maintaining circadian rhythms across different organisms. The study compared the transcriptomes of the two moth species to identify genes with varying expressions. Rosy maple moths prioritized their sense of smell, while oakworm moths invested more in visual genes.
The disco gene and its ‘zinc fingers’
One gene that stood out in the analysis is disco, which exhibited different expression levels during day and night hours. This gene, with additional zinc fingers, was found to be larger in moths compared to fruit flies. Mutations in the disco gene may contribute to the distinct behaviors and physical characteristics observed in these moth species.
Further research on gene changes in the wild could provide insights into speciation at a molecular level and shed light on the evolutionary processes shaping different species.
