Flexible safety barriers in the genome

Genome organisation, depth of intervention and speed of development

Until now, it has been assumed that mutations occur randomly in the genome and only natural selection determines which changes are established. However, recent research shows that the natural emergence of new mutations is not completely random but influenced by gene regulation and genome organisation. Besides the model plant Arabidopsis, bacteria, yeast and mammals have all been used for several scientific experiments on the mechanisms of heredity, gene regulation and genome organisation. It became evident from the experiments that several natural mechanisms protect important genomic regions against too many changes.

Gene regulation and genome organisation can use these natural mechanisms to accomplish two essential functions: firstly, continuous change and (if required) rapid adaptation to new environmental conditions, and secondly, stable inheritance, which is a precondition for the survival of a species. Evolution is dependent on the balance between chaos and order, change and stability, with gene regulation and genome organisation acting as nature’s flexible ‘safety barriers’.

The new genetic engineering (New GE) techniques are designed to override these mechanisms in the cells. Due to the technical processes used in New GE, the resulting intended and unintended patterns of genetic change (genotypes), as well as biological characteristics (phenotypes) and associated risks, can go beyond what is achieved by conventional breeding or evolution. The site of the genetic changes and the resulting gene combination can be specific to the NGT processes. Consequently, extreme variants of biological characteristics and new traits, which are unlikely to be achieved with conventional breeding, can result from NGT processes. Unintended effects may occur due to interactions in 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. The differences between conventional breeding and NGTs can be easily overlooked, but can, nevertheless, have serious consequences.

There are numerous and diverse risks which can affect ecosystems, agriculture and food production, e. g. changes in plant composition may impact wild animals, mammals, birds or insects and their food webs. Changes in the composition of plants can also impact plant interaction and communication with the environment. These risks can affect, e. g. insects (such as pollinators and beneficial species), symbiotic organisms (such as associated micro-organisms) or plant ‘enemies’ (such as pest insects). There are further specific risks associated with New GE organisms capable of spreading in the environment. Due to the diversity and complexity of interactions with the environment, there can also be next generation effects not observed in organisms developed in the laboratory, e. g. invasiveness.

Large numbers of GE organisms derived from NGTs, including various species with a wide range of different characteristics (intended or unintended), could be released into the same receiving environment within a short period of time. Depending on the scale of the releases, their duration and the characteristics of the organisms, these NGT organisms may also intentionally or unintentionally interact with each other. Even if distinct organisms are considered to be ‘safe’, uncertainties or even unknowns will emerge from their interactions with other NGT organisms released into the same environment.

Similar to environmental pollution with plastics and chemicals, it is not always an individual NGT-GMO which may create the real problems, but rather the sum of diverse effects on the environment. Without strict regulation of New GE, the uncontrolled release of large numbers of organisms with characteristics that have not evolved naturally can be expected to take place within short periods of time. This would result in an increased likelihood of damage to ecosystems, agriculture, forestry and food production.

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Further information: 
Q&A: Why ‘New GE’ needs to be regulated

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