First DNA editing of human embryo in the US
Reports are emerging from the US that Dr Shoukhrat Mitalipov, a research at the Oregon Health and Science University, has been the first US scientist to cause genetic alterations within the human embryo.
The reports are saying that this has surpassed work previously done in China, which had poor efficiency and raised serious questions about the precision of the alterations. Here, Dr Mitalipov has modified a large cohort of single cell embryos with high efficiency, using CRISPR.
We have talked about CRISPR in the past , however, in brief, it is a relatively new technique which allows the precise and efficient editing of DNA. While it does provide precise and efficient targeting, the risk of secondary alterations at off-target sites has been a consistent fear.
None of the embryos were implanted and thus were terminated within a few days, however, the possibility of correcting disease-causing genes using CRISPR is now a bigger possibility than ever before.
It is important to note that Dr Mitalipov has not yet published this research, meaning key details have been withheld and it has not been properly scrutinised by the scientific community, however, this may be a large sign that it may be time for a wider discussion on genetically modified individuals.
The modification of DNA within embryos is a gigantic step in the idea of genetic engineering, as this would alter the germ line. Most stem cell therapies or genetic therapies so far have looked into altering fully formed tissues, introducing the DNA into the type of cells found within the eye or pancreas. This has limited the introduction of edited DNA into the wider public. The alteration of the germ line would involve the introduction of the mutated DNA into the sexual organs, and consequently, the sperm and eggs, meaning that this would then be passed on to any subsequent children.
A couple of main fears arise from altering the germ line. Firstly, several mutations that may be detrimental in some situations can be advantageous in others. A perfect example would be sickle cell anaemia. It is only when both copies of the gene are mutated that the individual develops a severe blood condition involving the failure for red blood cells to properly maintain shape and structure, however, it is thought that the presence of one copy of the mutation protects from malaria which is heavily prevalent in Africa, where the sickle cell mutation is most prevalent. If we begin to remove these from the gene pool we could be removing resilience from certain threats unknowingly.
Along the same lines, animals have thrived by having genetic diversity. A population of genetically-similar individuals risks having nobody who is capable of adapting to new threats or alterations in their environment.
Looking at the ethics of the situation also raises dilemmas. The main issue being that of designer babies. As trends ebb and flow will we be able to discern generations by the presence of certain genetic details, will blondes be born in the 2040’s but be the old fad by 2050’s where everybody wants a brown-haired baby? Might we see the eradication of rarer traits such as ginger hair as reproduction undergoes mass-commercialisation? Some countries do not value their genders equally, so might we see a large shift in gender dynamics and how would this affect reproduction later on, or the attempted eradication of the LGBT community. All of these are just the tip of the ethical mind-field that is the genetic modification of embryos for non-medical purposes, and each should be carefully considered before we move any further down this path.
UPDATE (3/8/17): The paper has been released and looks to confirms the rumours.
Originally published at sciencewithalexblog.wordpress.com on July 28, 2017.
