Learn About The Genome Editing Or Gene Editing Technology

what is genome editing?

It is left to chance with classic genetic engineering and how often the desired gene is inserted into the genome. On the other hand, genome editing is relatively safe to determine where the intended change is placed.

Genetic engineering uses different transmission mechanisms to smuggle the genes into the cell. For example, a “mini-cannon” bombards the cell with the new genes at high speed, or bacteria are used as transporters. Where and how often a genetic modification occurs is random and influences whether and how the new gene functions and whether it may destroy other plant genes.

In classical genetic engineering, researchers have to search for a long time before finding a cell in which the genetic modification worked as intended.

Genome editing uses biological tools (proteins or RNA) to identify the exact sequence in the genome to be changed. Therefore, genetic modifications can be made more precisely with genome editing than with classical genetic engineering.

However, genome editing tools are often introduced into the cell using the same methods as in classic genetic engineering after the genome has been edited – as with traditional genetic engineering – a living being, for example, a plant, must be created from the modified cell.

The method most frequently used for targeted alteration of genetic information is the so-called “gene scissors” CRISPR / Cas.

Genome editing consists of modifying the genome of a cell with great precision. It is possible to inactivate a gene, introduce a targeted mutation, correct a particular mutation or insert a new gene. This genetic engineering technique uses modified nucleases, called “molecular scissors. “

These nucleases cut DNA at a predefined location in the genome, depending on its sequence. A natural DNA repair system (NHEJ for Non-Homologous End-Joining ) is then set in motion to “glue” together the two free ends generated by the cut. But this repair system introduces errors, leading to the mutation of the gene targeted by the nuclease. In this case, the mutation introduced is, therefore, random. 

It is also possible to modify the target sequence according to your wishes. It is then necessary to deliver to the cell, in addition to the nucleases, a DNA strand exhibiting the desired line, flanked by ends homologous to those of the cleavage site.

Another cellular repair system will then intervene (homologous recombination) and “incorporate” the DNA sequence provided at the time of repair, leading to its definitive insertion into the genome. 

What do we mean by new genetic engineering or genome editing?

New genetic engineering makes it possible to insert genetic changes in an organism targeted at specific points. The term encompasses various techniques. Some of these methods can be used to rewrite or edit “letters” (nucleotides) of the genetic information (genome) in one or more places. You can also use it to shut down parts of the genome or insert new genes (practically whole words).

The discovery of CRISPR / Cas, the so-called gene scissors, has pushed the development of genome editing an enormous step forward because it works many times better than previous methods. It can be applied to practically all organisms, i.e., plants, animals, bacteria, fungi, Viruses, and human cells. Therefore, it can be used in many areas, for example, biotechnology, medicine, primary research, and animal and plant breeding.

What is the difference between genome editing and classic genetic engineering?

It is left to chance with classic genetic engineering and how often the desired gene is inserted into the genome. On the other hand, genome editing is pretty safe to determine where the intended change is placed.

Genetic engineering uses different transmission mechanisms to smuggle the genes into the cell. For example, a “mini-cannon” bombards the cell with the new genes at high speed, or bacteria are used as transporters. Where and how often a genetic modification occurs is random and influences whether and how the new gene functions and whether it may destroy other plant genes. In classical genetic engineering, researchers have to search for a long time before finding a cell in which the genetic modification worked as intended.

Genome editing uses biological tools (proteins or RNA) to identify the exact sequence in the genome to be changed. Therefore, genetic modifications can be made more precisely with genome editing than with classical genetic engineering.

However, genome editing tools are often introduced into the cell using the same methods as in classic genetic engineering after the genome has been edited – as with traditional genetic engineering – a living being, for example, a plant, must be created from the modified cell.

The method most frequently used for targeted alteration of genetic information is the so-called “gene scissors” CRISPR / Cas.

What is unique and new about CRISPR / Cas? How does it work?

The CRISPR / Cas gene scissors are an essential tool in genome editing technology. It consists of two parts: the part that recognizes the section in the genetic information (genome) of the cell (recognition component) and the role that cuts it (cutting component). The recognition component brings the cutting component in the cell to the desired genome segment to switch off one or more selected genes, change, or insert new genetic information.

The recognition component consists of only a few letters and sometimes fits in different places in the genome. The gene scissors can therefore accidentally cut at these or similar recognition sites. So far, gene scissors have been used most frequently in plants and animals to permanently switch off genes or specific functions in one or more places.

CRISPR / Cas is also possible in genome regions that are naturally protected in the cell and are hardly accessible for classic breeding. You can also use CRISPR / Cas repeatedly. This is another reason why organisms that have been created using new genetic engineering can show profound genetic changes even if no additional genes have been inserted.

Is new genetic engineering at all?

New genetic engineering or genome editing is genetic engineering. The European Court of Justice ruled this in a landmark ruling in 2018. One reason for the decision is that genetic changes can be brought about faster, more extensively, and more profoundly through genome editing than traditional breeding or classic genetic engineering.

The risks are comparable to the dangers of classic genetic engineering. That is why in the EU, for example, plants for agricultural use that have been produced using new genetic engineering are subject to genetic engineering law. Before they can be approved, they must be checked for possible environmental risks and human health.

What are the side effects of genome editing?

Side effects are also possible with genome editing. On the one hand, the interventions in the genome are often not as precise as they should be. The process can result in further genetic modifications elsewhere than desired. The genetic modification of the genetic information in one or more places can have an unplanned effect on additional genetic information.

Remnants of the gene scissors can remain in the cell—a changed property results in further possible changes. For example, the ingredients of genome-edited plants or animals can change, which can change their susceptibility to diseases and pests, their nutritional value, and ecological functions.

The intended change can also lead to problems outside of the changed plant or animal species. For example, drought-resistant plants could spread into the environment and cause damage to natural habitats. Herbicide-resistant plants can encourage monoculture cultivation.

For these reasons, the comprehensive environmental risk assessment required by genetic engineering law is also essential for genome-edited plants.