Flies are quite adept at buzzing around, despite the fact that their wings are small in comparison to their bulky bodies. Now, new research published Nov. 17 in the journal Nature has uncovered the gene switch responsible for building the flight muscles in flies. Much like hummingbirds, flies have to flap their wings extremely fast to stay aloft. The fruit fly Drosophila melanogaster contracts and relaxes its flight muscles 200 times a second. Researchers at the Max Planck Institute of Biochemistry in Germany have found that a gene transcription factor called spalt creates these specialized muscles. Spalt is an important go between that ensures that genes get translated into functional proteins. Without it, flies develop only slow moving leg muscles. Humans can t fly, but our heart muscles contain spalt, according to study researcher Frank Schnorrer. That could mean that the factor is important in regulating heartbeat, although more research is needed.