HDR
Also written as: HDR — Homology-Directed Repair
A high-fidelity DNA repair pathway that uses a provided template to introduce precise edits at a Cas-induced break site. Always capitalised as an abbreviation.
Full Definition
Homology-directed repair (HDR) is a cellular DNA repair mechanism that uses a homologous template—either an endogenous sister chromatid or an exogenous donor DNA—to accurately repair double-strand breaks. In CRISPR editing workflows, HDR is exploited to introduce specific nucleotide changes, insertions, or corrections into the genome. Editors should note that HDR is written in full capitals and is contrasted with the error-prone NHEJ pathway. HDR efficiency is cell-type and cell-cycle dependent and is a key variable reported in gene-editing studies.
Usage
Usage note: Always abbreviated as 'HDR' after first use. Contrasted with NHEJ; the distinction is editorially significant in gene-editing manuscripts.
In Context
- "HDR efficiency was markedly reduced in post-mitotic neurons compared with proliferating cells." — Results section
- "A single-stranded oligodeoxynucleotide donor was supplied to facilitate HDR at the target locus." — Methods section