CCT conducted a five-year study, funded by the National Science Foundation (NSF), to investigate an online professional development course's impact on teachers' content and pedagogical knowledge as well as their students' knowledge. CCT worked in partnership with PBS TeacherLine New York and the Buffalo PBS affiliate WNED on the study, which involved New York State public high school 9th- and 10th-grade biology teachers whose students were eligible to take the state's Living Environment Regents Examination. Participating teachers took an online professional development course created by WGBH Teachers' Domain to support the development and use of inquiry-based approaches to teaching genetics and evolution.