GENETICS × TECHNOLOGY

Scissors Found in Bacteria

2012 CE

History · Contemporary · Holocene · Meghalayan

Bacteria keep mugshots of the viruses that attack them and use RNA copies of those sequences to guide a protein, Cas9, that cuts matching DNA. In 2012, biochemists showed the guide could be rewritten at will, and fused its two RNA parts into one programmable molecule: an enzyme that cuts DNA wherever you spell. Genome editing, until then a craft of bespoke proteins, became a tool any laboratory could aim.

Why it matters

CRISPR made editing genomes cheap, fast and general, and the first cures, for sickle cell disease among them, have already reached patients. It reopened, with real stakes, the questions Asilomar once rehearsed: edited crops, edited wild populations and, after one notorious experiment on embryos, edited human inheritance. A defence system invented by bacteria billions of years ago is now the sharpest pencil our species holds over its own text.

Dating & uncertainty

Two teams published in 2012, weeks apart: Jinek, Charpentier, Doudna and colleagues showed Cas9 guided by a designable RNA, and engineered the single-guide chimera; Gasiunas and Siksnys demonstrated the same RNA-directed cutting in a parallel system. The 2020 Nobel Prize in Chemistry went to Charpentier and Doudna, and the priority arguments, scientific and legal, are part of the event.

Sources

1. Jinek et al. (2012), Science · A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunitydoi:10.1126/science.1225829
2. Gasiunas et al. (2012), PNAS · Cas9-crRNA ribonucleoprotein complex mediates specific DNA cleavage for adaptive immunity in bacteriadoi:10.1073/pnas.1208507109
3. The Nobel Prize in Chemistry 2020, awarded to Emmanuelle Charpentier and Jennifer A. Doudna for the development of a method for genome editing. Institutional source: NobelPrize.org press release, accessed 2026-08-30.

Our species’ history as one day

23:59:563.8 s before midnight

if the 315,000 years of Homo sapiens were compressed into a single day