New Paper Sheds Light on Firefly Bioluminescence
LEWISBURG, Pa. — Fireflies and their fascinating luminous courtships have been the subject of childhood wonder and inspired scientific curiosity for centuries. Now, thanks to a team of researchers that included Bucknell University biology professor Sarah Lower (above), the world knows more about the genetics behind fireflies and their bioluminescence.
The team of 22 researchers from 15 institutions around the world were the first to sequence genomes on the chromosomal level of two firefly species — including the Big Dipper firefly, a common inhabitant in North American meadows and suburban lawns — and a related click beetle species. From those genome maps, the researchers were able to identify the location of the luciferase genes — the key genes in the luminous reaction — and the additional genetic ingredients to the reaction.
Their findings were published today in the online journal eLife.
“Ours is the first genome sequence of any firefly species to an almost chromosomal level. In this paper, we look at the genome sequences of two firefly species — a Japanese species and a North American species — and the click beetle, so the genetic story of how bioluminescence came about is a little clearer,” said Lower, who came to Bucknell this fall from the Department of Molecular Biology & Genetics at Cornell University. “The data from these species provides a more comprehensive picture of how bioluminescence has evolved in beetles.”
The research can aid conservation strategies to help protect fireflies from changes in climate and habitat, and also assist in the production of synthetic firefly light used in biomedical and agricultural research.
To produce the light, a specialized small molecule, luciferin, is broken-down by a specialized enzyme, luciferase, in the light-emitting organ of the firefly. From examining which genes were turned on in the light-emitting organ of the firefly, the researchers were able to generate a list of genes possibly involved in the light reaction. They were also able to find the DNA of bacteria that are likely living within firefly cells that may also participate in the reaction.
Fireflies use the light in mating.
“Fireflies are famous for these bioluminescent signals that we see in the summertime. They use them as mating signals — like a Morse Code, with each species having its own flash pattern to identify and locate and choose mates,” Lower said.
The genetic data gathered in this research will provide a foundation to determine the diversity, genetics and population structure of fireflies and develop more effective conservation strategies for their preservation.
“This work, combined with work I published last month, suggests that firefly populations are localized and so, if a firefly population is eliminated in one area, it may be difficult to get it back,” Lower said. “So we really need to conserve these small populations. One possibility is that they’re greatly impacted by light pollution because they can’t find each other for mating.”
Funding for this research was raised through Experiment, an online platform designed to raise money from individuals for scientific discoveries. Ninety donors contributed more than $10,000 to fund their project.