---
_id: '2412'
abstract:
- lang: eng
text: 'Background: The CRISPR/Cas system is known to act as an adaptive and heritable
immune system in Eubacteria and Archaea. Immunity is encoded in an array of spacer
sequences. Each spacer can provide specific immunity to invasive elements that
carry the same or a similar sequence. Even in closely related strains, spacer
content is very dynamic and evolves quickly. Standard models of nucleotide evolutioncannot
be applied to quantify its rate of change since processes other than single nucleotide
changes determine its evolution.Methods We present probabilistic models that are
specific for spacer content evolution. They account for the different processes
of insertion and deletion. Insertions can be constrained to occur on one end only
or are allowed to occur throughout the array. One deletion event can affect one
spacer or a whole fragment of adjacent spacers. Parameters of the underlying models
are estimated for a pair of arrays by maximum likelihood using explicit ancestor
enumeration.Results Simulations show that parameters are well estimated on average
under the models presented here. There is a bias in the rate estimation when including
fragment deletions. The models also estimate times between pairs of strains. But
with increasing time, spacer overlap goes to zero, and thus there is an upper
bound on the distance that can be estimated. Spacer content similarities are displayed
in a distance based phylogeny using the estimated times.We use the presented models
to analyze different Yersinia pestis data sets and find that the results among
them are largely congruent. The models also capture the variation in diversity
of spacers among the data sets. A comparison of spacer-based phylogenies and Cas
gene phylogenies shows that they resolve very different time scales for this data
set.Conclusions The simulations and data analyses show that the presented models
are useful for quantifying spacer content evolution and for displaying spacer
content similarities of closely related strains in a phylogeny. This allows for
comparisons of different CRISPR arrays or for comparisons between CRISPR arrays
and nucleotide substitution rates.'
author:
- first_name: Anne
full_name: Kupczok, Anne
id: 2BB22BC2-F248-11E8-B48F-1D18A9856A87
last_name: Kupczok
- first_name: Jonathan P
full_name: Bollback, Jonathan P
id: 2C6FA9CC-F248-11E8-B48F-1D18A9856A87
last_name: Bollback
orcid: 0000-0002-4624-4612
citation:
ama: Kupczok A, Bollback JP. Probabilistic models for CRISPR spacer content evolution
. BMC Evolutionary Biology. 2013;13(1):54-54. doi:10.1186/1471-2148-13-54
apa: Kupczok, A., & Bollback, J. P. (2013). Probabilistic models for CRISPR
spacer content evolution . BMC Evolutionary Biology. BioMed Central. https://doi.org/10.1186/1471-2148-13-54
chicago: Kupczok, Anne, and Jonathan P Bollback. “Probabilistic Models for CRISPR
Spacer Content Evolution .” BMC Evolutionary Biology. BioMed Central, 2013.
https://doi.org/10.1186/1471-2148-13-54.
ieee: A. Kupczok and J. P. Bollback, “Probabilistic models for CRISPR spacer content
evolution ,” BMC Evolutionary Biology, vol. 13, no. 1. BioMed Central,
pp. 54–54, 2013.
ista: Kupczok A, Bollback JP. 2013. Probabilistic models for CRISPR spacer content
evolution . BMC Evolutionary Biology. 13(1), 54–54.
mla: Kupczok, Anne, and Jonathan P. Bollback. “Probabilistic Models for CRISPR Spacer
Content Evolution .” BMC Evolutionary Biology, vol. 13, no. 1, BioMed Central,
2013, pp. 54–54, doi:10.1186/1471-2148-13-54.
short: A. Kupczok, J.P. Bollback, BMC Evolutionary Biology 13 (2013) 54–54.
date_created: 2018-12-11T11:57:31Z
date_published: 2013-02-26T00:00:00Z
date_updated: 2021-01-12T06:57:20Z
day: '26'
ddc:
- '576'
department:
- _id: JoBo
doi: 10.1186/1471-2148-13-54
file:
- access_level: open_access
checksum: 029c7e0b198c19312b66ecce3cabb22f
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:17:15Z
date_updated: 2020-07-14T12:45:40Z
file_id: '5268'
file_name: IST-2015-397-v1+1_1471-2148-13-54.pdf
file_size: 518729
relation: main_file
file_date_updated: 2020-07-14T12:45:40Z
has_accepted_license: '1'
intvolume: ' 13'
issue: '1'
language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
page: 54 - 54
publication: BMC Evolutionary Biology
publication_status: published
publisher: BioMed Central
publist_id: '4514'
pubrep_id: '397'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'Probabilistic models for CRISPR spacer content evolution '
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 13
year: '2013'
...