A teardrop tattoo beneath the eye has symbolic, context dependent meaning. One meaning is a war trophy; the wearer has murdered as many humans as there are tears on his/her face. I think the CRISPR region, now famous for its potential in gene editing and talk of ‘designer babies’, is the microbial analog of the infamous war trophy: tattooed tears.
Tattoo Tears (Prison Context)
Aside from protists that consume bacteria, viruses are a bacteria's worst nightmare. Viruses that only attack and infect bacteria, bacteriophages, are estimated to knock out > 40% of bacteria in the ocean. Clustered Regularly Inter-spaced Short Palindromic Repeats (CRISPR) is a segment of bacterial* DNA that provides them some immunity against viral attacks. How does it work?
When bacteria is attacked by a virus, the bacteria is usually destroyed. However, those that survive the attack keep a piece of the defeated virus (the war trophy) in its genome just in case it encountered that virus again; It would know how to defeat it again, like a vaccine.
In the genome of most bacteria you will find an area for war trophy storage called the CRISPR region. There are 13 war trophies in a strain of S. thermophilus' CRISPR region.
Electron micrograph of S. Thermophilus colony
Linear representation of the genome of S. thermophilus.
Zoom in view of the CRISPR region.
Zoom in within the CRISPR region
*CRISPRs have also been observed in archaea.
https://www.nature.com/scitable/definition/bacteriophage-phage-293
