CRISPR Cas 9 – “We are far from understanding the ‘concert of genes’ in the human genome”

A Moratorium to protect the human genome is needed

by Dres  med Ursula and Walter Knirsch, Zurich

CRISPR Cas 9, this is the acronym of “Clustered Regularly Interspaced Short Palindromic Repeats”. A palindrome may be read forward and backwards such as “Was it a cat I saw?”. Cas 9 means CRISPR associated Sequence 9.

Background

A few years ago researchers found CRISPR Cas 9 in bacteria and identified it as a bacterial anti-viral immune system. In the process of analysing this defense system it became clear that it constitutes an instrument of gene technology if applied to other cell types. Ever since and increasingly so, CRISPR Cas 9 has been used world-wide. Analogous terms for CRISPR Cas 9 are genetic scissors, gene surgery, genome editing or precision medicine.
This article deals with the way of function including examples in humans, plants and animals, as well as the risks of this new CRISPS Cas 9 technology, especially regarding its socio-political and ethical consequences.

How does CRISPR Cas 9 work

The nuclei of all body cells contain our genetic information, encoded in desoxyribonucleic acid (DNA) as genes in the chromosomes. The sum of all genes defining our selves is referred to as the genome. By means of CRISPR Cas 9 a genetic reprogramming may be achieved here. Metaphorically speaking this may be compared to a text editing computer programme, which finds certain word groups and exchanges them for others when the button “search and replace” is hit. Similarly, CRISPR Cas 9 carries out a search for certain gene domains in the DNA and replaces them with others. CRISPR Cas 9 consists of three subunits: (1) a target RNA, equivalent to the genetic sequence which is to be changed, (2) another RNA sequence, connected to the molecular scissors, and (3) the cutting enzyme Cas 9. This way CRISPR Cas 9 searches the DNA and finds the sequence in question, cuts it out and may replace it by another sequence if wanted.

More than just a new method

This recently developed biochemical-genetic method appears to be an efficient tool to remove, alter or amend certain genetic sequences. Researchers interfere significantly with the genes and therefore the genomes of plants, animals and human (somatic) as well as embryonic (germ­line) cells by means of CRISPR Cas 9. The technology is “attractive” for being easy to perform, fast and cheap.
Long-term consequences of these genes being irreversibly altered may be huge, since this is a massive interference with nature. The risks for future generations are incalculable.
A moratorium for the protection of the genome is therefore necessary. Any uncontrolled tampering with the genome has to be stopped in order to avoid unforeseeable and possibly lethal consequences for nature.

The Swiss referendum on the Reproductive Medicine Act (RMA) and CRISPR Cas 9

A special political relevance of CRISPR Cas 9 results from the Swiss legislative proposal on the Reproductive Medicine Act (RMA) which will be decided on in the referendum on 5 June. The so-called germline cells connected with pre-implantation diagnostics are especially important here.  In humans these include sperm and egg cells as well as embryos. To this day they are protected by law, including the Swiss constitution, and strictly speaking they are not subject of the referendum on 5 June 2016. However, in case the proposed RMA law was to be accepted by the Swiss electorate, a high number of “superfluous” embryos suddenly would become available. Many interest groups would focus on these embryos and they would be interesting as material for CRISPR-Cas 9-technology in the long run. In England CRISPR Cas 9 experiments with human embryos have already been allowed and from the history of similar law revisions in the last 15 years one may suspect that Switzerland might be pressured into legally accepting universal uncontrolled CRISPR Cas 9 procedures on different cell types and genetic sequences in future.  

A clear No of the people to the RMA proposal is therefore crucial. This would stop any uncritical und uncontrolled use of CRISPR Cas 9.

CRISPR Cas 9 in somatic versus germline cells

Efforts to potentially learn how to treat genetic diseases with CRISPR Cas 9 (to this day there is still a long way to go!) in affected children or adults may be justified, since such specific interference with somatic cells is associated with an “individual risk” only. These changes would not be inherited by the progeny of the patient.  Nevertheless a careful investigation of efficacy, possible adverse affects and risks of such potential therapy attempts is required.  
Genetic tampering with germline cells, on the other hand, would be given to the next generation and therefore constitutes an unwarranted risk. Potentially it could cause irreversible changes in the human genome, which defines all of us. Long-term consequences might be grave, resulting in massive irreversible damages in the human nature and the sequelae of future generations cannot be foreseen today.

A clear moratorium is needed

International awareness of the grave insecurities and dangers arising from this new technology of CRISPR Cas 9, as well as possible social and ethical consequences, is insufficient at present. Some scientists who helped to establish this method are already campaigning for a moratorium. Recently the Leopoldina, i.e. the National Academy of Science in Germany, warned: “We are still far form understanding the concert of the genes in the human genome.”
A clear moratorium is needed, which should address the currently more or less uncontrolled practice in several countries in appropriate wording. This moratorium has to make sure that the employment of methods CRISPR Cas 9 is safe, transparent and conducted according to ethical standard. Any tampering with the human germline has to remain banned.
Therefore: An international moratorium for the protection of the human genome is crucial. Uncontrolled “access” of the human genome has to be stopped, to prevent potentially fatal and irreversible consequences for the human nature.
There must be no employment of CRISPR Cas 9 in human germline cells, until potential risks are entirely clear. Genetic germline changes are irreversible!
Chinese scientists have already experimented on human embryos “left over” from in vitro fertilisation. The results caused tremendous alarm and irritation in the international scientific community. The intended changes occurred only in a small portion of treated embryos. On the other hand, several changes were caused in other parts of the genome that had not been targeted. Such unintended results are referred to as “Off target effects”. The gene scissors CRISPR Cas 9 seems to cut not only where it is supposed to. Obviously, the hailed precision may fail. Moreover, inherent repair mechanisms of the cell are effective enough to reduce effectiveness of CRISPR Cas 9.

So-called “nature-identical” genetic engineering – consequences for agriculture

It has to be stressed that genetic changes due to CRISPR Cas 9 cannot be proven afterwards which undermines any post-hoc control. This is important for gene food, which was manufactured using CRISPR Cas 9 and which are euphemistically referred to as “nature-identical”.
The moratorium therefore has to make sure that food and crops genetically modified by CRISPR Cas 9 have to be declared to be genetically modified Organisms (GMO). This is not the case in a genetically modified mushroom, for-instance, which was manufactured by means of CRISPR Cas 9 in the US recently. It has already made its way into the vegetable counter and therefore the food chain.

More uncritical employment of CRISPR Cas 9 in animals

Mosquitoes, acting as malaria vectors, may be subject to population changes by means of introgression of new genes into their germline using CRISPR Cas 9, which render the mosquitoes resistant to the plasmodium species causing malaria. This genetic change prevents the next generation mosquitoes from transmitting malaria to humans. The genetically modified mosquitoes are supposed to eventually replace the non-modified ones in the ecosystem in the course of a “mutagenic chain reaction”. Due to their fast reproduction rates, that could be the case within one season. Despite no field trial has ever been conducted there are already researchers calling for a release of such GMO mosquitoes into the wild. Nobody can predict, however, how these mosquitoes might in turn change the eco-system.
There are already dogs rendered more muscular and Cashmere goats with longer hair, thanks to CRISPR Cas 9 gene modification. Obviously an economic impetus is driving these efforts. At Harvard Medical School 62 genes have already been altered successfully in pigs.

Conclusion

After the discovery of the DNA double helix (1953) and the design of the polymerase chain reaction method for the sequencing of the genome (1983), CRISPR Cas 9 and its employment in the first attempt of Chinese researchers (2013) to edit human DNA seems to be a third “milestone” in risk to develop into a dangerous, if ruthlessly un-reflected technology with nightmarish potentials. A clear moratorium is what we need to prevent that from happening!    •