Harvardscientists have genetically engineered the hearts of fruit flies to keep pacewith a flashing blue light. Why, you ask? Well, fruit flies are prone to heartattacks, so such a tool may help scientists who are using these buggers forresearch. Also, doctors may want to one day to build pacemakers that arecontrolled by light and tweaked genes rather than electricity and wires.
Scientists have used this technique – optogenetics – to control the hearts ofzebrafish and mice, but only during early stages of life or through chestsurgery. With fruit flies, heart rates can be controlled at every stage of lifeand by just shining a light on the insects, since their skin is somewhattransparent. This video shows an adult heart tuned to 8, 9 and 10 beats per second.