My lab explores the role that telomeres play in the biology of mammalian cells. In mammals, including humans, chromosomes are capped by protective structures called telomeres. Without these structures, cells may mistake the ends of normal chromosomes for “broken” DNA and attempt to repair them—a process that actually causes damage and can lead to cancer. But not all cells have telomeres. Some bacteria form a protective “loop” at the tips of their chromosomes; others get around the problem by having chromosomes that are circular. Our aim is to remove the telomeres from mammalian chromosomes and either cap them with bacterial loops or circularize them. We will then introduce these altered chromosomes into cells and observe how they are handled and whether the cells can tolerate these telomere alternatives. Because telomere dysfunction is associated with cancer and aging, this work will provide a new understanding of how cancer occurs and new anti-cancer therapies.