The efforts of our laboratory are split evenly between experimental and computational biology. We develop new experimental methods to sequence single cells and isolate rare subpopulations and develop new analytical approaches to detect variants and apply statistical methods to these data sets. We focus mainly on breast cancer to understand the role of clonal diversity in the evolution of invasion, metastasis and response to chemotherapy. We are also using these tools to study rare tumor cell subpopulations including circulating tumor cells and cancer stem cells. Our goal is to understand the role of clonal diversity in tumor evolution so that we can exploit this diversity for therapeutic vulnerabilities and improve diagnostic tools and the early detection of cancer. We fully expect that applying these tools to human patients will lead to reduced morbidity in breast cancer.