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Boston University was where Margulis held a junior faculty position. Margulis's academic career began at Boston University, where she served as a junior faculty member. Her research there focused on the evolution of eukaryotic cells, particularly the role of endosymbiosis in the origin of mitochondria and chloroplasts. This work laid the foundation for her groundbreaking theory of endosymbiosis, which revolutionized our understanding of cellular evolution.