Science and technology have completely revolutionized the world...and it’s only moving faster.
But advances in technology have not always been met with praise. In the last ten years, gene editing has become the center of an ethical debate, and many people question whether science has gone too far.
The potential benefits of editing human genomes include eradicating specific genetic mutations, harmful alterations, and hereditary health conditions. Making edits to a person’s genetic code could significantly reduce their odds of developing certain cancers, blood disorders, blindness, muscular dystrophy, and even erectile dysfunction.
While all of these possibilities are generally "welcome", opponents of human genome editing have raised real concerns about whether or not gene editing is ethical or morale – and even whether it's safe.
What Is Gene Editing?
Gene editing (short for genome editing) is a type of gene-based engineering where modifications are made to specific DNA sequences in an organism with a goal of changing its genetic code.
All living cells contain a genome sequence, an instruction manual of sorts. Adding, removing, or altering the DNA that creates this sequence can change the characteristics of a cell.
The concept of gene editing has been around since the 1970s, but limited technology at the time prevented it from progressing significantly. Gene editing made some breakthroughs in the 90s as technology allowed more research and experimentation. There have been significant developments in gene editing in the last thirty years.
Scientists now deploy several types of gene editing technology, and the three most common include:
- CRISPR (clustered regularly interspaced short palindromic repeats): The most common, affordable, and efficient system for gene editing. CRISPR targets the DNA of a genome sequence that contains base-paired RNA. Scientists discovered the CRISPR-cas9 system in bacteria that use this method to destroy viruses.
- ZFN (zinc finger nucleases): Proteins made of zinc fingers bind to at least three different DNA strands in a genome sequence. Cutting these fingers will fuse two nucleases and cause them to bind to each DNA strand and replicate.
- TALEN (transcription activator-like effector nucleases): Each DNA strand in a genome sequence has its own TALE domains that scientists can engineer to bind to specific DNA strands much easier than ZFNs. When TALE molecules are cut, they replicate and bind to each DNA strand.
Why Is Gene Editing Being Studied?
One proposed purpose of gene editing is to repair genetic flaws that offspring might inherit.
There are thousands of genetic disorders a generation can pass to the next. Sickle cell anemia, Down syndrome, cystic fibrosis, and hair loss are all passed along genetically.
It’s possible that editing the DNA of embryos while in utero could prevent babies from inheriting these genetic conditions. Genetic edits that change heritable traits are called germline edits, as opposed to "somatic" edits that are not inherited. Germline genome editing could allow us to "fix" future generations (or worse) and create truly genetically modified humans.
In theory, we could eliminate genetic disorders entirely with germline editing.
Gene editing is not just about removing harmful DNA strands. It can also replicate and copy cells that might be beneficial in fighting cancer or infectious diseases like HIV/AIDS. Every cell has a natural defenses to help protect it from external threats such as bacteria or viruses. Certain weak links in the “chain” can allow the threat to penetrate the cell and infect it.
Removing a genetic defect and replacing it with a stronger DNA strand can help enhance a cell's defenses to particular viruses, for instance, and protect it from harm or help it target specific pathogens.
Is Gene Editing Currently Being Used?
Using gene editing on humans is a heated debate, with both sides standing firm.
Human gene editing is currently not banned in the United States, but a moratorium has been imposed by the Food and Drug Administration and National Institutes of Health.
There is currently no ban or moratorium on food gene editing, and the agriculture industry has pounced on the opportunity to make more and enhanced food sources. The first GMOs (genetically modified organisms) were released commercially in 1992; genetic modification is nothing new in the world of agriculture.
Since then, technology has allowed for further genetic modification of food that can benefit farmers and consumers. Altering the genetic sequence of a crop can lead to a greater crop yield, a reduced cost of production, enhanced nutritional value, and stronger resistance to pests and diseases.
Is Gene Editing Ethical?
The application of gene editing or gene therapies has raised various ethical and safety concerns.
In 1996, then-president Bill Clinton signed the Dickey-Wicker Amendment. The amendment prohibits using Congressionally-appropriated funding to create or destroy human embryos for research purposes.
After the amendment, scientists have relied on private funding to further the advancement of gene editing. The Dickey-Wicker Amendment was renewed in 2009 and remains active to prevent federal research into gene editing.
Congress passed the amendment in response to ethical concerns about the nature of editing genes and DNA sequences. The argument centers around three primary issues: safety, consent, and equity.
Gene Editing Safety
The primary debate around gene editing is whether or not it’s safe to modify human DNA and genetic sequences. Although the International Summit on Human Gene Editing largely concurred that gene editing is safe based on existing research, they could not yet recommend using it on living humans.
Some experts believe that current technology is sufficient, and embryos could greatly benefit from being altered.
Others claim that potential mistakes could result in lifelong disabilities or death. Since these consequences are avoidable, they insist that any potential rewards are not worth the risk.
Another common argument stems from the perceived inevitability of non-therapeutic gene editing and enhancement procedures. Human gene editing may begin altruistically and focus on curing disease, eventually leading to unnecessarily risky human augmentations.
Gene Editing Consent
It’s standard practice for any medical facility to require a signed letter of consent for treatments, surgeries, or procedures. Consent signifies that you're aware of the potential risks versus benefits, and that you understand the treatment you’re about to receive.
One of the significant concerns with gene editing is that it’s impossible to get informed consent from an embryo or future generations.
There can always be unintended consequences no matter how safe the research suggests that gene editing may be. Signing up for an experimental surgery means that you accept these risks and will live with the results. Altering an embryo's genes could lead to permanent and disastrous consequences that will be passed down in perpetuity.
The counterargument to this stance is that parents often make life-altering decisions for their unborn children, like choosing to smoke or drink during pregnancy, which would be no different. There doesn’t appear to be any realistic options for compromise on this facet.
Gene Editing Equity
An argument made by some opponents of gene editing is that the technology will only be available to the wealthiest and affluent members of society. With a growing disparity in healthcare already underway, gene editing will further the divide. The poorest members of society likely won't have access to gene editing and would be left to deal with genetic conditions as treatment options would fade away.
The argument also posits that genetic engineering could develop a superior class of humans, creating an artificial evolution. A type of people with enhanced immunities and reduced weaknesses would be treated differently and have better opportunities in life than those with natural genetic sequences.
Gene editing is a complicated subject, and the ethics debate continues.
Gene editing might someday cure genetic mutations that contribute to genetic disorders. Sickle cell, cystic fibrosis, Huntington’s disease, muscular dystrophy, and possibly even erectile dysfunction involve specific genetic flaws that gene editing could someday alter.
The question of ethics remains a sticking point. Until that debate ends, germ-line and embryonic gene editing in humans will stay on the shelves.