@@ -22,7 +22,7 @@ Bacteria and their phages have co-existed for billions of years. The pressure of
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@@ -22,7 +22,7 @@ Bacteria and their phages have co-existed for billions of years. The pressure of
## A brief history of anti-phage systems
## A brief history of anti-phage systems
The first discovered anti-phage system, a Restriction-Modification (RM) system, was described in the early 1950s ref{doi=10.1128/jb.64.4.557-569.1952,10.1128/jb.65.2.113-121.1953}. In the following decades, a handful of other systems were discovered :ref{doi=10.1016/j.mib.2005.06.006}. In 2007, CRISPR-Cas systems were discovered to be anti-phage systems :ref{doi=10.1126/science.1138140}. As CRISPR-Cas systems and RM systems are extremely prevalent in bacteria, it was thought for some years that the antiviral immune system of bacteria had been mostly elucidated.
The first discovered anti-phage system, a Restriction-Modification (RM) system, was described in the early 1950s :ref{doi=10.1128/jb.64.4.557-569.1952,10.1128/jb.65.2.113-121.1953}. In the following decades, a handful of other systems were discovered :ref{doi=10.1016/j.mib.2005.06.006}. In 2007, CRISPR-Cas systems were discovered to be anti-phage systems :ref{doi=10.1126/science.1138140}. As CRISPR-Cas systems and RM systems are extremely prevalent in bacteria, it was thought for some years that the antiviral immune system of bacteria had been mostly elucidated.
Following these two major breakthroughs, knowledge of anti-phage systems remained scarce for some years. Yet, in 2011, it was revealed that anti-phage systems tend to colocalize on the bacterial genome in defense-islands :ref{doi=10.1128/JB.05535-11}. This led to a guilt-by-association hypothesis: if a gene or a set of genes is frequently found in bacterial genomes in close proximity to known defense systems, such as RM or CRISPR-Cas systems, then it might constitute a new defense system. This hypothesis was tested systematically in a landarmark study in 2018 :ref{doi=10.1126/science.aar4120} leading to the discovery of 10 novel anti-phage systems. This started the uncovering of an impressive diversity of defense systems in a very short amount of time :ref{doi=10.1038/s41579-023-00934-x}.
Following these two major breakthroughs, knowledge of anti-phage systems remained scarce for some years. Yet, in 2011, it was revealed that anti-phage systems tend to colocalize on the bacterial genome in defense-islands :ref{doi=10.1128/JB.05535-11}. This led to a guilt-by-association hypothesis: if a gene or a set of genes is frequently found in bacterial genomes in close proximity to known defense systems, such as RM or CRISPR-Cas systems, then it might constitute a new defense system. This hypothesis was tested systematically in a landarmark study in 2018 :ref{doi=10.1126/science.aar4120} leading to the discovery of 10 novel anti-phage systems. This started the uncovering of an impressive diversity of defense systems in a very short amount of time :ref{doi=10.1038/s41579-023-00934-x}.
