Each person in the United States generates five or more pounds (2.3 kilograms) of waste a day: about the weight of a medium bag of sugar. More than half of that garbage is buried and stored in landfills. Increasingly, however, cities are promoting recycling programs, often getting schools involved so students can learn about recycling and follow these practices at home.
A person in a Scandinavian country (such as Sweden, Denmark, or Norway) generates about the same amount of waste as an American. People in developing countries generate less waste than Americans or Europeans; for example, a person in India generates about three-fourths of a pound (0.34 kilograms) per day. Still, every country must find a way to process the garbage that each of its residents generates every day, month, and year.
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.