Chris Burge admits it’s been hard to choose a research focus. In high school he won math contests but in college majored in biology. He traveled to Nicaragua to see if medicine was his calling but wound up teaching people there about computers. He finally settled on the interface between biology and mathematics and returned for graduate study in math at Stanford University, his alma mater. The sophisticated computer program he developed there, called Genscan, predicts the locations of genes in the human genome and what proteins they produce. Released in 1997,Genscan is the most popular program of its type. Geneticists and molecular biologists are using it to identify human disease genes and potential drug targets and are applying it to agriculture. It is available free on the Web for nonprofit use and has been licensed to dozens of companies. Now at MIT’s biology department, Burge has developed a companion program, GenomeScan, that compares known proteins to increase the accuracy of Genscan predictions. He hopes to answer fundamental questions that could shed light on how human genes are expressed.