Talk of the Nation

Reporting in Cell Metabolism, researchers write that when people who lead relatively sedentary lives worked out the DNA in their muscle fibers changed almost immediately. Scientists also found caffeine had the same effect on isolated rodent muscles. Study co-author Juleen Zierath discusses the DNA modifications.

The New Horizons Mission blasted off toward Pluto in 2006; it's on course to arrive in Pluto's neighborhood in 2015. Mission leader Alan Stern discusses the journey of the spacecraft, and why he thinks Pluto is still a planet. Plus, the mission to get Pluto on a commemorative stamp.

Between the resident emu and the newborn goats, Harvard's Concord Field Station, located in Bedford, Mass., has a menagerie feel. The lab researches how different animals move--which requires lots of animals, and gadgets to facilitate and document their motion.

Reporting in the Astrophysical Journal, scientists write of a massive collision between two galaxy clusters. By studying the cosmic remnants of that smashup, they say leftover dark matter isn't behaving as current theory predicts. Astrophysicist Andisheh Mahdavi discusses this dark matter mystery.

It's been an unusually warm winter in some parts of the country, with springtime temperatures and very little snow. How is nature responding? Purdue entomologist Tom Turpin and horticulturalist Kristin Schleiter of the New York Botanical Garden discuss how an early spring affects flower buds, beetles and bees.

Reporting in Nature, researchers write they have deciphered the genetic code of the gorilla, the last of the great apes to have its genome sequenced. Study co-author Aylwyn Scally discusses what the data reveal about the evolution of humans and other apes.

When you crunch into a potato chip or take a spoonful of chocolate mousse what you experience is more than just the taste of the food. In her book Taste What You're Missing, Barb Stuckey discusses why truly experiencing food involves all five senses and offers tips on how to get more enjoyment from your next meal.

After the terrorist attacks on 9/11, some law enforcement agencies adapted crime mapping tactics into what is known as ethnic mapping. Some Muslims welcome ethnic mapping as a useful approach to preventing terrorism. Others say the surveillance amounts to domestic spying and racial profiling.

Kony 2012 is not your usual viral video. A thirty-minute film by the nonprofit group Invisible Children, it hopes to raise support for the arrest of Joseph Kony, the leader of the Lord's Resistance Army. Freelance reporter Michael Wilkerson fact checks the film and explains the controversy.

The divorce rate among people 50 and older has doubled in the past 20 years, according to research by Bowling Green State University sociologists Susan Brown and I-Fen Lin. Their paper, "The Gray Divorce Revolution," examines the factors driving the trend.