English
Deutsch
The patterns of genetic change resulting from New Genetic Engineering techniques (New GE) is often unique and cannot be achieved with conventional breeding. This also applies to cases in which no additional genes are inserted into the genome.
Researchers working for the US company, Calyxt, targeted a group of gluten proteins (gliadins) in wheat that are thought to cause inflammatory bowel diseases (celiac disease). These genes occur within a large family of genes which are present in so-called gene clusters (i. e. in multiple copies) at different locations in the genome. So far, conventional breeding has not been able to reduce the large number of genes and gene copies. With the help of the CRISPR/Cas gene scissors, researchers succeeded for the first time in 2018 in switching off a large number of these genes: 35 out of 45 genes that produce gliadins were ‘switched off’. The result is a unique pattern of genetic modification in wheat.
However, this can also trigger unintended biological properties, e. g. changes in ingredients. For this reason, these plants must be examined in detail to determine risks, even if no additional genes are inserted to achieve this new gene combination. The European Food Safety Authority (EFSA) also came to the conclusion that the large number of mutations is far beyond any previously risk-assessed plant. According to EFSA, it is necessary to prevent the accumulation of any protein fragments associated with initiation of the inflammatory cascade.
This example shows: New GE can override natural mechanisms in the cells that maintain and restore the original gene functions. New GE can thus result in plants and animals with extreme biological characteristics, which go beyond what can be achieved in conventional breeding. Unintended effects may occur due to interactions within the complex networks of genes, proteins and other biologically active molecules. Such unintended effects can still emerge even in cases where the genetic intervention is targeted and precise.
