Geneticist Amita Sehgal of the University of Pennsylvania was recently studying fruit flies in her lab when she noticed something peculiar. The insects slept normally when bathed in light for 24 hours a day but tossed and turned when shifted from one day/night cycle, or “time zone,” to another. It turns out they were suffering from something akin to serious jet lag.

While some scientists are looking to the future, trying to push the human body beyond its natural limits, others are fighting the same old scourges we’ve always faced. Here, an update on five particularly stubborn ailments and promising research avenues that might finally lead to cures.

CANCER
What goes wrong When DNA is dam-