The race to become the next mayor of San Diego is heating up. Democratic Congressman Bob Filner officially threw his hat in the ring yesterday. Filner joins a field that includes Republicans Bonnie Dumanis, Nathan Fletcher and Carl DeMaio. State Senator Christine Kehoe is also considering running for mayor in 2012. Who else could join party? And, what do each of the official candidates bring to the race? We speak to San Diego Mesa College Political Science Professor Carl Luna about the mayor's race.