# Efficient iterative CRISPR/Cas9 editing using sid-1 co-conversion and feeding RNAi in Caenorhabditis elegans

## TL;DR

This paper introduces a method to efficiently create complex genetic strains in C. elegans using CRISPR/Cas9 and sid-1 RNAi techniques.

## Contribution

A novel CRISPR/Cas9 co-conversion strategy using sid-1 RNAi for iterative gene editing in C. elegans.

## Key findings

- Using sid-1 loss-of-function CRISPR reagents reduces candidate screening from thousands to tens of F1 progeny.
- Restoration-of-function CRISPR reagents enable visible RNAi phenotype screening for efficient strain development.
- The optimized sid-1 CRISPR design increases the success rate of co-conversion events for multiple gene edits.

## Abstract

We present a sid-1 loss-of-function and restoration-of-function CRISPR/Cas9 co-conversion protocol in Caenorhabditis elegans. Introducing CRISPR reagents that induce sid-1 loss-of-function can produce survivors on lethal RNAi foods while reagents that induce sid-1 restoration-of-function can be screened for restoration of visible RNAi phenotypes. Both methods efficiently reduce the pool of candidates from hundreds or thousands of F1 progeny to tens with minimal experimenter effort. Furthermore, our optimized sid-1 CRISPR design allows a high ratio of CRISPR reagents targeting the gene of interest, maximizing successful co-conversion events. The interconvertibility of the sid-1 locus readily enables this strategy to be leveraged to iteratively create complex strains with multiple gene edits.