GE-CRISPR-Cas Waxy Corn was produced with a CRISPR-Cas9 gene knockout approach to inactivate the corn granule-bound starch synthase 1 (waxy) gene that encodes an enzyme catalyzing production of amylose. The result is a specialty corn with the starch composed exclusively of amylopectin.

GE-CRISPR-Cas Waxy Corn was developed using two guide RNAs which lead to the deletion of the DNA sequence between the two targeted sites and the inactivation of the waxy gene.

Two waxy deletion alleles, a 4-kb or 6-kb deletion, were described by Gao et al. (2020), thus it is not clear which deletion is present in the final plant line.

GE-CRISPR-Cas Waxy Corn, is a null segregant line that contains the targeted deletion but does not contain any inserted DNA.

Sources:

1. USDA APHIS inquiry

2. Gao et al., (2020), Superior field performance of waxy corn engineered using CRISPR-Cas9. Nature Biotechnology 38:579-581.