A double-strand break is the easy part; what you do with it decides the edit. US10526590B2 - "Compounds and methods for CRISPR/Cas-based genome editing by homologous recombination," issued January 7, 2020 to Agilent Technologies - claims the editing method anchored to the homology-directed repair (HDR) pathway, and that anchoring is the claim's center of gravity.

Cells repair a Cas-induced break by one of two dominant routes: error-prone non-homologous end joining (NHEJ), or precise homology-directed repair using a supplied template. A claim that recites editing 'by homologous recombination' carves out the precise-repair route specifically. That is narrower than a claim to any CRISPR cut, and it is deliberately so - HDR-based precise correction is the commercially valuable mode for fixing point mutations.

“The present invention relates to guide RNAs comprising adaptor segments having one or more modifications, and their use in homologous recombination by CRISPR:Cas systems. The modified adaptor segments are resistant to degradation by RNaseH.”— U.S. Patent No. 10,526,590 source

The CPC assignment is spare here - C12N 9/22 alone - which tells you the office read this primarily as a Cas-nuclease-class invention applied to a repair method, not as a sprawling composition family. A spare CPC profile often signals a tightly-scoped claim set rather than a defensive thicket.

Why does the repair-pathway limitation decide so much? Because a competitor practicing CRISPR editing that relies on NHEJ-based disruption - knocking a gene out rather than precisely correcting it - is arguably outside a claim drawn to homologous recombination. The limitation both narrows the claim past the dense cutting-machinery prior art and confines enforcement to programs doing templated correction.

For the landscape, this is a reminder that 'CRISPR patent' is never a sufficient description. The estate fractures by mechanism - cutting, base editing, prime editing, NHEJ disruption, HDR correction - and a grant tied to one repair pathway reaches only the programs that use it.