Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) in bacterial and archaeal DNA have recently been shown to be a new type of antiviral immune system in these organisms. We here study the diversity of spacers in CRISPR under selective pressure. We propose a population dynamics model that explains the biological observation that the leader-proximal end of CRISPR is more diversified and the leader-distal end of CRISPR is more conserved. This result is shown to be in agreement with recent experiments. Our results show that the CRISPR spacer structure is influenced by and provides a record of the viral challenges that bacteria face.
Highlights
Clustered regularly interspaced short palindromic repeats (CRISPR) in bacteria and archaea have recently been suggested to provide adaptable immunity in these organisms [1,2,3]
Clustered regularly interspaced short palindromic repeats (CRISPR) in bacterial and archaeal DNA have recently been shown to be a new type of antiviral immune system in these organisms
Our results show that the CRISPR spacer structure is influenced by and provides a record of the viral challenges that bacteria face
Summary
New spacers are always added to the leader-proximal end [9]. To avoid infinite growth of CRISPR, an old spacer is dropped when CRISPR is longer than a certain length [10]. The Kronecker delta function i;k is 1 if spacer type i matches virus strain k; otherwise, it is 0 This model is modified from the classic immune response model with antigenic variation [13]. The initial value for the differential equations are naive bacteria whose CRISPR provide no resistance to viruses because their spacers are empty. At the beginning, both positions have high diversity of spacers.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
