The CRISPR sequences are a crucial component of the immune systems of bacteria. Photo: Supplied
It's been dubbed the biggest advance in the world of genetic engineering but scientists are still trying to discover more about what the gene-therapy CRISPR-Cas9 can do.
It's often described as molecular scissors, and can be used to find and cut out a specific short DNA sequence with a gene.
Now new research has found many humans are immune to the main protein of CRISPR, which means they would reject it.
Simon Morton asked the lead author of the study, Matthew Porteus from Standford University about the latest findings.
