Science has fascinated Serafim Batzoglou since he was 12, when he watched Carl Sagan on TV, at home in Athens, Greece. Today, Batzoglou is unlocking the mysteries of the genetic structure of organisms, and he has recently led development of two important programs for deciphering genomes. Arachne, released in 2002, was the first widely available tool for assembling full genomes from fragments of genes. Researchers used it to assemble the mouse genome, creating a blueprint for studying the human genome (mice and humans share 95 percent of their genes). Scientists also used Arachne to sequence another scientific workhorse, the fruit fly. The second program, Rosetta, helps compare the human and mouse genomes. Although Batzoglou’s algorithms draw great praise, he says he’s simply lucky his programming skills can be applied to Biology. Now a Stanford University assistant professor of computer science, Batzoglou heads development of Lagan, a software tool for aligning long sequences of DNA so scientists can compare the genetic structures of humans and other creatures. Batzoglou is not a biologist, but his work may help rewrite the book of evolution.