Erez Lieberman-Aiden, 29

When Erez Lieberman-Aiden started his PhD in applied math in 2003, evolutionary theory couldn't handle the complex shapes of real-world populations. So he helped it adapt by combining it with specialized mathematical tools. His advances at the Harvard-MIT Division of Health Sciences and Technology have allowed evolutionary biologists to include more variables in their models.

His next challenge: "People talk about the evolution of culture and language, but I found myself wondering whether evolution is really relevant to culture," Lieberman-Aiden says. Working with Google, he and colleagues are building tools that can scan massive collections of digital texts and quantify how often a word--say, communism--appears in those from a particular era and place. This makes it easy to observe the movement of ideas, culture, and language across time and space.

Recently, Lieberman-Aiden has shifted his research toward genomics. Scientists can determine the sequence of bases in DNA, but they've had no way to know the genome's overall structure. L­ieberman-Aiden has co­developed a method that determines both sequence and structure--revealing, for instance, conformational changes that bring two genes close even though they're far apart along the length of a chromosome.--Erika Jonietz