Mice that can stutter like humans may seem pretty striking. But what really renders researchers speechless is the enigmatic genetic glitch that causes stuttering.
Researchers led by Terra D. Barnes of Washington University discovered that their genetically-engineered mice stutter due to DNA defects in a humdrum “housekeeping” gene. This gene codes for a protein that simply places a "routing tag" on certain enzymes that shred cellular trash. The tag ensures that the shredding enzymes end up in chambers called lysosomes, basically the cell’s garbage disposal. It’s a mundane cellular activity, yet mutations in the same process in humans have also been linked to stuttering—a bizarrely specific condition for such a general gene. And, so far, scientists have no idea why the two are linked.
Nevertheless, the engineered mice presented with similar symptoms as humans who stutter. Though mice obviously don’t talk as humans do, they emit ultrasonic and squeaky whistle-like songs that are coded with information. Researchers have already spent plenty of time studying these songs in detail. In particular, they’ve studied the “isolation calls” belted out by newborn mice when their mothers aren’t around.