The size of the immune repertoire of bacteria
ORAL
Abstract
Some bacteria and archaea possess an immune system, based on the CRISPR-Cas mechanism, that confers adaptive immunity against phage. In such species, individual bacteria maintain a "cassette" of viral DNA elements called spacers as a memory of past infections. The typical cassette contains a few dozen spacers. Given that bacteria can have very large genomes, and since having more spacers should confer a better memory, it is puzzling that so little genetic space would be devoted by bacteria to their adaptive immune system. Here, we identify a fundamental trade-off between the size of the bacterial immune repertoire and effectiveness of response to a given threat, and show how this tradeoff imposes a limit on the optimal size of the CRISPR cassette.
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Presenters
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Serena Bradde
Physics Department, University of Pennsylvenia
Authors
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Serena Bradde
Physics Department, University of Pennsylvenia
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Armita Nourmohammad
Max Planck Institute for Dynamics and Self-Organization, Physics Department, University of Washington, University of Washington
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Sidhartha Goyal
Physics Department, University of Toronto, University of Toronto, Univ of Toronto
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Vijay Balasubramanian
University of Pennsylvania, Physics Department, University of Pennsylvenia