CRISPR/Cas was used to simultaneously change two genetic sites (four alleles) in canola. The goal was to reduce grain losses prior to harvesting. Grain losses occur when the canola seeds are ripe and when, for instance, the wind blows through the plants. The researchers emphasise that this method was much faster than conventional breeding and there were fewer mutations in total in the genome. The plants did actually seem to lose fewer grains.
There were, however, unintended genetic changes. The reason: the first step in producing the transgenic canola plants involved using 'old genetic engineering' methods (transformation with Agrobacterium tumefaciens). This is necessary for the protein (enzyme) of the gene scissors to be produced in the cells, and requires a gene construct for the formation of the enzyme to be inserted into the genome of the plants. It is only in the second step that the plant genes are 'cut' by the gene scissors to knock out their function. This two-stage process is typical of gene scissors technology, and similar procedures are currently used in most New GE applications in crops.
The procedure resulted in components of the gene constructs, including bacterial genes used as tools in gene transfer, being unintentionally inserted into at least 5 different sites in the genetic material of the plants. These additional DNA sequences were initially overlooked in preliminary investigations. The unwanted results were only found when the whole genome (whole genome sequencing) was analysed.
This example shows: Plants generated with New Genetic Engineering must be thoroughly examined for unintended genetic changes. All stages of the processes must be included. If unintended genetic changes are overlooked, they can spread rapidly in large populations. Genetically engineered canola can persist in the environment and can also cross with related species.