Die Kurzantwort
Not every genetic problem needs the text rewritten. Sometimes a gene simply needs to be louder or quieter. Disabled CRISPR proteins can be used as programmable volume controls — parked on a gene to block it, or carrying an amplifier to boost it — without changing the DNA at all.
CRISPRi uses dCas9-KRAB to repress transcription reversibly; CRISPRa uses dCas9 fused to activator domains to increase it. Epigenetic editors write or erase DNA methylation and histone marks for potentially durable, heritable changes in expression without sequence alteration. These approaches avoid every double-strand-break hazard, at the cost of durability that must be demonstrated rather than assumed.
When adjusting beats rewriting
Sources
- National Human Genome Research Institute
Talking Glossary of Genomic Terms ↗