Sen. Elizabeth Warren's ex-husband co-founded a DNA testing company and wrote one of the first computer codes for making genetic comparisons. Jim Warren's career involved him in the kinds of genetic testing that Elizabeth Warren controversially invoked this month to prove that she had Native American ancestry. One of the two other co-founders of his testing company, FamilyTreeDNA, has worked with Carlos Bustamante, the Stanford University geneticist who administered a DNA test at Elizabeth Warren's request.