University of Maryland Biology Assistant Professor Philip Johnson was invited to speak at UMD's Bioscience Day 2019 on November 12, 2019.
His talk will be on "Here a CRISPR, There a CRISPR: Why Not Everywhere a CRISPR?"
Abstract: Just like humans, bacteria and archaea must constantly fend off viral infections. Microbes have developed many anti-viral defense mechanisms, the most fascinating of which is CRISPR-Cas, which serves as a remarkably effective adaptive immune system. While humans have recently hijacked this system for use in precision genome editing, it evolved naturally as a means for microbes to remember past viral pathogens and to defend themselves against future infections by precisely chopping up remembered viral genomes. Despite CRISPR-Cas being found scattered throughout the tree of life (in >40% of sequenced bacteria and archaea) as well as providing near-perfect protection from infection given a matching viral memory, viruses continue to exist and many species of microbes consistently lack a CRISPR-Cas system. I will explore these puzzles and propose hypotheses to explain coexistence and the ecological-evolutionary patterns of CRISPR-Cas incidence.
