The CRISPR editing tool has its origins in microbes — bacteria and archaea that live in obscene numbers everywhere from undersea vents to the snot in the human nose.
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The process works like this: A virus injects its genetic material into the cell. Sensing this danger, the cell selects a little strip of that genetic material and adds it to the spacers in the CRISPR cluster. This step, known as immunization or adaptation, creates a list of encounters a cell has had with viruses, plasmids or other foreign bits of DNA over time — neatly lined up in reverse chronological order, newest to oldest.
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Just as people can develop autoimmune reactions against their own bodies, bacteria and archaea can accidentally make CRISPR spacers from bits of their own DNA — and risk chewing up their own genetic material. Researchers have seen this happen.
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What do microbes pay attention to? What do they ignore? CRISPRs offer a bright new window on such questions and, indeed, already are unearthing novel phages and facts about who infects whom in the microscopic world.
Read full, original post: CRISPR had a life before it became a gene-editing tool
