Scientists have for the first time genetically engineered a butterfly, inserting a jellyfish gene into an African butterfly so that its eyes fluoresce green.
The butterfly, Bicyclus anynana, serves as an important subject for studies of how genes control development and how those controls evolve, says Antónia Monteiro of State University of New York (SUNY) at Buffalo. She and her colleagues figured out how to use molecular techniques to transform the butterfly and open new research opportunities in genetics, she says. The researchers describe their work in an upcoming issue of the Royal Society of London’s Biology Letters.
“I think the transformation is a very important tool,” comments Daniel Bopp of the Zoological Institute of the University of Zurich, whose team in 2001 made the first genetically modified housefly. “It’s a very targeted way to try to understand the function of a gene,” he says.
It’s been more than 20 years since researchers first genetically engineered an insect, the laboratory fruit fly. In the past decade, the pace has picked up, and biologists have worked out how to manipulate a wide variety of other insects, including several mosquitoes, screwworms, and two moths—the silkworm and the pink bollworm.
To get genes into a new organism, researchers depend on bits of DNA called transposons, which naturally infiltrate a host’s genes. Monteiro, working with Jeffrey M. Marcus of Western Kentucky University in Bowling Green and Diane Ramos of SUNY Buffalo, ferried the jellyfish gene in modified forms of the transposons Hermes, which was originally from a housefly, and piggyBac, from a cabbage looper moth.
The researchers chose the jellyfish gene for a green fluorescent protein that other researchers had used to create glowing green eyes in houseflies and some other insects.
The team injected the gene and a modified transposon into each of more than 10,000 butterfly eggs. About 95 percent of the eggs died. Of the survivors, 5 percent getting piggyBac and 10 percent getting Hermes transposons passed along green-fluorescing eyes to their offspring.
Monteiro plans to use this technique to study genes suspected of creating spots on butterfly wings (SN: 2/15/03, p. 104: Available to subscribers at How the Butterfly Gets Its Spots). Previous research has shown that similar genes in fruit flies control top-bottom orientation, leg development, and other developmental milestones. Monteiro will, for example, add extra copies of one of these genes and turn it on in unusual places. Ultimately, she says she wants to know, “How is it that the same old genes acquire these totally novel functions in butterfly wings?”