“Retro-Cascorder: Recording Gene Expression Order in DNA by CRISPR Addition of Retron Barcodes”, Santi Bhattarai-Kline, Sierra K. Lear, Chloe B. Fishman, Santiago C. Lopez, Elana R. Lockshin, Max G. Schubert, Jeff Nivala, George Church, Seth L. Shipman2022-06-02 (gene editing)⁠:

[blog; media] Biological processes depend on the differential expression of genes over time, but methods to make physical recordings of these processes are limited.

Here we report a molecular system for making time-ordered recordings of transcriptional events into living genomes. We do this via engineered RNA barcodes, based on prokaryotic retrons¹, which are reverse-transcribed into DNA and integrated into the genome using the CRISPR-Cas system². The unidirectional integration of barcodes by CRISPR integrases enables reconstruction of transcriptional event timing based on a physical record via simple, logical rules rather than relying on pre-trained classifiers or post-hoc inferential methods.

For disambiguation in the field, we will refer to this system as a Retro-Cascorder.