In 2018, a CRISPR-Cas gene scissors application succeeded in simultaneously altering several genes in wild type tomatoes. ‘Cuts’ to six genes changed bushy tomato plants with small tomatoes into plants with tomatoes that look similar to those currently on the market. The Brazilian, German and US authors reported that they were able to replicate the results of decades of breeding in a very short space of time. They stated, in addition, that the resulting genetically engineered tomatoes would have a much higher concentration of healthy ingredients.

‘Multiplexing’ is the term used to describe the parallel modification of several hereditary traits in parallel. Although in this case no additional genes were inserted, the results are astonishing: the number of tomatoes as well as their size, shape and ingredients were changed in just a few steps and within a short time. Although the gene variants resulting from the genetic engineering were already known from other tomato varieties, they now need to be seen in a new genetic context, i. e. wild  tomato plants. The result is a new gene combination that was not previously possible. In essence, although there was no repetition of traditional breeding, a completely ‘new’ tomato with a previously unknown composition of ingredients was created.

The European Food Safety Authority addressed the associated uncertainties in regard to risk assessment (EFSA 2022). According to EFSA, there are no conventionally-bred tomato varieties in existence that could be used as a comparator to verify the safety of the CRISPR tomato.

This example shows: While in conventional breeding it was possible to gain experience over many years and in several stages, ‘multiplexing’ now eliminates all these intermediate steps. Even though the result looks very similar to a conventionally-bred tomato, the composition of the ingredients in the new CRISPR tomato is different to those in previous tomato varieties. The depth of intervention and the speed of the genetic changes is associated with new risks and uncertainties for humans and the environment.

Publication year: 
2023

Further information: 
EFSA Scientific Opinion
Publication “De novo domestication of wild tomato using genome editing”