Dr. Bart M. G. Smits is an Affiliate Assistant Professor in the Department of Pathology & Laboratory Medicine at the Medical University of South Carolina (Charleston, SC) and Senior Manager of Genetic Sciences and Compliance at Taconic Biosciences (Albany, NY), with more than 15 years of experience in rat genetics. Having received extensive training in genetics and functional genomics, Dr. Smits chose to specialize in breast cancer genetics after completing his Ph.D. at Utrecht University in 2005. He joined Dr. Gould’s laboratory at the University of Wisconsin (Madison, WI) for postdoctoral training, where he sought to explain molecular genetic mechanisms underlying human breast cancer susceptibility by studying non-protein-coding variants associated with the disease. During this time, Dr. Smits mastered the mammary gland transplantation technique described in this paper and published multiple studies involving the procedure. Dr. Smits' laboratory currently uses unique genetically engineered rat, mouse, and human cell-based models to investigate genetic elements involved in breast cancer susceptibility. Recently, Dr. Smits published a research article using reciprocal mammary gland transplantation, which revealed a non-mammary cell-autonomous effect of Cdkn1b (p27) ablation on mammary gland development (Ding, Shunkwiler, et al. 2019, PLoS Genetics).