CRISPR
Cas Enzyme Variant Selector
Pick the best Cas9 or Cas12a variant for your locus and payload.
Pick the best Cas9 or Cas12a variant with PAM reach, fidelity, and payload scoring inside Helix Studio, the Genome IDE for programmable biology.
System of Record →Section 1
What the tool is
The Variant Selector ranks Cas enzymes for your locus, balancing PAM availability, fidelity, and delivery footprint.
Section 2
Why scientists care
Picking a nuclease is often guesswork—teams default to SpCas9 even when better fits exist.
Section 3
How Helix solves it
Scans your region for PAM density across supported variants
Section 4
How the algorithm works
We blend PAM availability, model implied on-target efficiency, and published fidelity tiers into a composite score.
Section 5
Try it in Helix Studio
Select a locus, view viable PAM coverage per nuclease, and adopt the top-scoring variant.
Section 6
FAQ
Do you include new high-fidelity variants?
Yes—high-fidelity Cas9/Cas12a variants are included with regularly updated PAM tables.
Can I lock delivery format?
Set AAV, LNP, plasmid, or RNP and Helix adjusts payload budgeting accordingly.
Will my existing guides transfer?
Guides stay linked; if a guide becomes incompatible with a new nuclease, Helix flags it with fixes.