In trying to define a fundamental role for BRCA1 in breast cancer, we took advantage of the evolutionary distance between humans and yeast to identify proteins and/or processes that have the ability to interact functionally with BRCA1 in yeast; these BRCA1-interacting partners were identified by finding yeast deletions that suppress BRCA1-induced lethality. The gene discussed is BRCA1; the disease is breast carcinoma.