But he took an introductory course in human developmental and regenerative biology (HDRB) when it was a new interdisciplinary concentration in the Faculty of Arts and Sciences. “The Stem Cell and Regenerative Biology (HSCRB) Department [the home for the concentration] does an excellent job of training scientists in the ways that they teach and test material,” he said. “Before taking [the introductory course] SCRB10 with Bill, I had the impression that stem cell biology was a highly esoteric field,” he said. They also observed that the stressed stem cells were labeled by a protein called Calreticulin on their surface that acted as an “eat me” signal. Stem cells lacking Calreticulin, or having just small amounts of it, were not eaten and seemed to be encouraged to expand.