Mammalian females ovulate periodically over their reproductive lifetimes, placing significant demands on their ovaries for egg production. Whether mammals generate new eggs in adulthood using stem cells has been a source of scientific controversy. If true, these "germ-line stem cells" might allow novel treatments for infertility and other diseases. However, new research from Carnegie's Lei Lei and Allan Spradling demonstrates that adult mice do not use stem cells to produce new eggs. Their work is published by the Proceedings of the National Academy of Sciences the week of April 29.

When a mouse smells a cat, it instinctively avoids the feline or risks becoming dinner. How? A Northwestern University study involving olfactory receptors, which underlie the sense of smell, provides evidence that a single gene is necessary for the behavior.

Nesting green sea turtles are benefiting from marine protected areas by using habitats found within their boundaries, according to a U.S. Geological Survey study that is the first to track the federally protected turtles in Dry Tortugas National Park.