Genome pioneer Craig Venter and a team of scientists have successfully turned one species of bacteria into another. Venter says the research could mark the first steps toward being able to create artificial life by inserting an entirely synthetic genome into a bacterial cell.

Scientists have derived a new type of mouse stem cell. They say it is a closer match to human cells than the stem cells currently available. Guests discuss what the new discovery could mean for the use of embryonic stem cells in medicine.

New evidence suggests that giant penguins once lived in a Peruvian desert more than 40 million years ago in the middle and late Eocene period. Researchers in Peru unearthed fossils of two species of ancient penguins, one of which stood over five feet tall and wielded a seven-inch beak.

From Atkins, to The Zone, to Jenny Craig, Americans are trying to slim down. But with so many diets and dieters, why is the nation collectively getting bigger? Gina Kolata, author of the new book Rethinking Thin, talks about why the country's obsession with waistlines isn't translating into weight loss.

Scientists tracking the surprising things that (literally) come out of a baby over the course of a year have been able to trace a timeline of the development of bacterial ecosystems within the human gut. Scientists are learning more about how our intestinal tracts become colonized with bacteria.