The genetic editing of human embryos is an ethical topic. The science is already available, although research continues to refine knowledge of it. We take a look at the challenges of gene editing after distinguishing between various terms.
Gene Editing and Genetic Engineering
Before getting into the topic, it is useful to understand the difference between gene editing and genetic engineering. Gene editing is also known as genome editing. Both gene editing and genetic engineering are techniques utilized in molecular biology.
In genetic engineering, genes are artificially manipulated. This involves making some modifications and recombining RNA or DNA. This is done to improve an organism’s traits. Foreign genetic material is inserted. The techniques used include the biolistic, vector, and plasmid methods.
When DNA is added, removed, adapted, or replaced in animals, bacteria, and plants, this is genome editing. There is no addition of foreign genetic material. The methods utilized are CRISPR/Cas9, meganucleases, transcription activator-like effector nucleases (TALENs), and Zinc-finger nucleases (ZFNs).
What is Cell Line Engineering?
Gene editing is inclusive of cell line engineering. The latest technologies put a break in the double-stranded helix at the point in the DNA where the modification is targeted. The cell will attempt to repair itself and it is during this phase that the gene sequence can be altered.
This is not without its challenges. The nucleases (or cutting enzymes) used to make the break require them to be applied to the correct sequence, a challenge known as specificity. If this is achieved most of the time, it is called cutting efficiency. Getting the cell to effect repairs to the DNA according to the preferred new gene order is edit efficiency.
Human Gene Editing
One study found that CRISPR genome/gene editing can have very negative consequences. For example, a human embryo may be modified inadvertently in undesirable or unintended ways.
Humans have had the ability to modify DNA since the 1970s. However, the methods and techniques in use nowadays are cheaper, quicker, and more accurate. The aim of gene editing is to eradicate certain diseases, like blindness, cancer, hemophilia, and sickle cell syndrome.
Starting in 2015, scientists have moved beyond working with people. Newer experiments use CRISPR to target sperm, ova, and even human embryos. When an embryo’s genes have been suitably modified, it is possible to insert the embryo into a womb to create a pregnancy with a genetically modified pre-natal human. The changes that were made will be present in the neonate and all of its descendants. Many countries have outlawed these experiments. Despite it being illegal, there are still some scientists who would like to pursue this.
Has Human Gene Editing been Successful?
One scientist in China achieved the birth of a set of twins who were the result of gene editing in 2018. He used the platform of the Second International Summit on Human Genome Editing to announce the birth, and no doubt to gain attention for his achievement. This public relations campaign has not had the effect of making it legal to use a modified embryo to start a pregnancy. The public names given to the twin girls are Nana and Lulu. These babies were born prematurely (twins often are), but nobody knows what has become of them since. For an update on China’s policies concerning gene editing of humans, click here.
As spokesperson for the Center for Genetics and Society, its Executive Director, Marcy Darnovsky condemned the experiment. The Center advocates for human rights, dignity, and social justice in the field of biotechnology using human subjects or cells.
The sperm cells used for conception came from a father who was infected with HIV. Fortunately, this was not transferred to his offspring. The experiment was not entirely successful as one copy of the modified gene in one child was not changed and the baby showed indications of mosaicism.
The Dangers of Gene Editing in Humans
Darnovsky warned that the creation of children such as Nana and Lulu can lead to unfairness. For example, a genetically modified child may have superior skills that make it impossible for natural humans to compete with them. He was also concerned that rich parents would seek out genetic improvements to their children, creating a superior race.
At the Third International Summit on Human Genome Editing, the participants agreed that it is still too early to apply new technologies for gene editing as there is no way to predict what would happen to future generations of children of a genetically modified human embryo. There are still multiple errors being made with the technology, making it too risky. It is also impossible to predict what the health of such children would be like. The committee felt that a widespread debate publicly is needed before opening the doors to genetic editing of human embryos. The conditions under which it could be considered are yet to be realized. These conditions are:
- It has been approved legally
- Efficacy and safety standards are met
- Testing and developments should be carried out under severe oversight
- Governance is in place and is responsible.
There are concerns over the Summit’s approach. This is mainly because the discussion’s focal point seems to have shifted. Initially, in 2018, the discussion centered around the rightness or wrongness of the genetic editing of human embryos and whether it should be allowed at all. More recent meetings of the committee considered the technical problems that needed to be resolved to enable alterations to be made safely.
Another criticism of the committee is that the debate has been limited to a small minority of researchers. The implications of the genetic editing of human embryos are too significant to be confined to a group. Public consideration of this use of technology has to take place. Finally, society is entitled, as a whole, to determine the limits placed upon the scientific community. Just because we can do something does not mean that we should be allowed to do it. Eugenics is perceived as immoral, favoring those with money, while poorer parents would not be able to have ‘designer children’ with carefully chosen traits and health conditions.
Regardless of the stance taken, it is vital to weigh in on discussions around the genetic editing of human embryos.
