For decades, there was a belief about HIV/AIDS and how it spread to the United States. The common theory was that one man, Canadian-born flight attendant Gaetan Dugas, was responsible, almost like a modern version of "Typhoid Mary."
He was often referred to as Patient Zero. But new evidence has emerged that seems to have debunked this story.
We talk to Professor Michael Worobey, the Department Head of Ecology and Evolutionary Biology at the University of Arizona. He led a team of researchers that published their study this week in the scientific journal, Nature.
Click the blue audio player above to hear the full interview.