As the third decade of the twenty-first century rolls on, advancements in genetic engineering, a leading area of biotechnology, continue to gain momentum. Humans are now capable of making applied and consistently transmitted changes to the genetic composition of living things, with impacts on organisms and our environment that are already being felt.
Genetic engineering certainly offers a lot of promise, but many people are concerned that it may harbor devastating consequences that humanity has not yet comprehended. In this article, we’ll take a closer look at the genetic engineering pros and cons, to help you evaluate if it is truly a good thing.
What is genetic engineering?
The National Human Genome Institute defines genetic engineering as a process that uses laboratory-based technologies to change or manipulate the packaged DNA (genes) of an organism. Genetic engineering uses invasive techniques to change the genetic makeup of cells.
By moving genes within and across species boundaries, scientists can obtain their desired observable traits in the host organism’s phenotype. This video from the Massachusetts Institute of Technology (MIT) explains the basics:
Scientists manipulate and modify sequences of DNA by removing them from organisms. They can also artificially synthesize RNA and complementary DNA strands using the polymerase chain reaction (PCR). Organisms can also be genetically modified (GM) through the removal of specific gene sequences, carried out using DNA-cutting enzymes known as restriction endonucleases.
Novel gene sequences can then be inserted or spliced into the DNA of a host organism. This is called recombinant technology. These genes encode instructions for the production of particular protein products. The host organism transcribes and translates the gene, leading to the production of the gene products with novel effects on the modified organism (gene expression).
What is a genetically modified organism?
A genetically modified organism or GMO is an organism that has undergone genetic engineering and is permanently different from the original wild-type or natural organism. This is because the genetic sequences added or removed change gene expression and protein production in the GMO organism leading to:
- An altered physical appearance
- The production of a specific substance, that may have positive or negative effects
- Increased resistance to a specific disease
- The eradication of specific genetic conditions in the organism or its offspring
A brief history of genetic engineering
The geneticists Stanley N. Cohen and Herbert W. Boyer were the first scientists to cut up DNA into fragments and insert gene sequences into an organism. In 1973 they successfully added new genes to the plasmid of E. Coli bacteria. A year later, Rudolf Jaenisch inserted foreign DNA into the genome of a mouse, creating the first GM animal.
By the end of the 1970s, the recombinant technology used by these scientists had already become commercialized with the production of human insulin by GM bacteria in 1982. Genetic engineering expanded to food crops and livestock, with GM food introduced to consumers in the 1990s. The Flavr Savr, a GM tomato introduced in 1994 was developed to have a longer shelf-life and by the early 21st century almost all the corn produced in the US was GM, with strained developed to be more resistant to drought and pests.
Genetic engineering technologies and techniques
Genetic engineering now uses several techniques to change the genes of living organisms. The methods vary in sophistication, cost, and application and certain jurisdictions may restrict their use. Here are some leading genetic engineering technologies:
- Recombination technology: This is the original form of genetic engineering that uses restriction enzymes that can cut sequences of DNA that are then inserted into the host organism’s genome.
- Zinc finger nucleases: This gene editing technology uses a special nuclease enzyme fused with a three base pair DNA-binding domains for more precise DNA binding site recognition when editing genes.
- CRISPR-Cas9: Clustered Regularly Interspaced Short Palindromic Repeats or CRISPR- based genome editing is one of the most advanced forms of genetic engineering. It adapts a technique used by bacteria to evade genetic damage from viruses. CRISPR has become widespread because of its accessibility, low cost, and precision. It is thought to have been used in some extremely controversial experiments including gain-of-function virology research, and the gene editing of embryos.
- Base editing: This simpler gene editing technique makes single base substitutions without inducing risky double-stranded breaks in the genome. Double-strand breaks are a serious form of DNA damage that can lead to the deletion of genes, cell death, or the development of cancer. Base editing offers the promise of curing genetic diseases caused by errors in a single base in the DNA (single nucleotide polymorphisms).
- Prime editing: This contemporary form of gene editing uses an enzyme that can create single-strand breaks in DNA (Cas9 nickase) along with a complex (pegRNA) that acts as a template for the reverse transaction attachment of the desired bases to the site where the DNA has been broken. This avoids double-strand breaks and is considered safer for human therapeutic uses.
Genetic engineering applications
Because all living things have DNA the applications and implications of genetic engineering are understandably vast. The rapid standardization and commercialization of genetic engineering techniques have enabled companies to develop applications in diverse sectors spanning agriculture, healthcare, environmental conservation, and industry, without any public consultation or consent.
Key applications of genetic engineering include:
- The study of gene expression and function using experiments to add or delete gene sequences and portions.
- The development of pharmaceutical products like antibiotics, hormones, and antibodies using GMOs.
- The creation of disease, pest, and drought-hardy crops.
- The production of potent enzymes for industrial detergents, cheese production, and fermentation.
Pros of genetic engineering
Genetic engineering is a key driver of the biotechnology sector which advocates that altering the expression of genes can be targeted, controlled, and beneficial to life on Earth. Here are some benefits of genetic engineering:
1. A greater understanding of how DNA and genes work
Genetic engineering evolved from the study of DNA, and experiments were undertaken to understand how genes work. Once eminent scientists like Watson and Crick and Rosalind Franklin had established the molecular structure of DNA in the 1950s, work began in earnest to understand its function.
The Discovery of the four key classes of enzymes that acted on DNA, helicase, primase, DNA polymerase, and ligase, equipped scientists with tools to work with DNA, cutting and splicing it in specific places. This experimentation with DNA and its effects on gene expression underpin genetic engineering and has continued to expand the field of genetics.
2. The production of medicines
Biotechnology is already an integral part of healthcare and genetic engineering is used to produce medicines for many common conditions. Medicines that are produced by genetic engineering are either:
- Biological medicines that a GMO has produced.
- GMOs that are used as medicinal agents.
Essential medicines that are derived from GMOs or are GM products include:
- Monoclonal antibodies
- Hormones including insulin and growth hormone
- Pancreatic enzymes
Genetic engineering has made it possible to produce these humanized biological agents at scale so that patients can access them when needed. For example, recombinant insulin is now the main type of insulin used by Type I diabetics rather than the animal-derived insulins that were originally used to treat this condition.
3. A promise of cures for genetic diseases
The manipulation and editing of gene sequences using genetic engineering technologies offer an as-yet-unrealized promise of curing genetic diseases. Point mutation diseases such as sickle cell disease and hemophilia A and B, caused by errors in a single or a limited number of nucleotides in a gene sequence could be frankly cured by having the genetic error corrected.
This type of genetic engineering is gene therapy. Though gene therapy has captured the public imagination, offering hope for cures for devastating genetic diseases, this area of science is not adequately advanced to treat patients in a consistent, reliable, or safe manner.
4. Development of more productive and resilient crops
Genetic engineering is considered a key area of innovation in agriculture. After millennia of painstaking cross-pollination and plant breeding, genetic engineering can achieve dramatic changes in the characteristics and performance of crops almost instantly.
Genetic engineering has been used to develop crops with novel gene insertions that confer protection against pests and diseases or raise the crop’s tolerance to pesticide use. GM crops achieve their enhanced resilience by producing protein products that have these beneficial effects, like plants that express proteins known to inhibit pests.
New breeding techniques (NBT) routinely use genetic engineering alongside conventional breeding to produce crops that are more resilient and productive. Examples of genetically engineered crops include non-browning potatoes, mushrooms, and apples, soybeans with an improved oil profile, and flavor-enhanced fruit and vegetables.
5. Enhanced livestock breeds
Genetic engineering has also extended to livestock, with modern techniques like CRISPR used on pre-implantation embryos to alter specific traits and characteristics. Scientists implant the gene-edited embryos in the womb of a surrogate animal to gestate, producing a generation of transgenic animals with an altered genetic profile.
The gene editing of animals is understandably controversial and governments restrict the use of these animals as food in many parts of the world. Advocates for transgenic livestock point to the enhancements that can be achieved, which can improve livestock health, fertility, resilience, and the nutritional content of meat.
6. The creation of new commercial sectors
Genetic engineering has been integral to developing biotechnology as an industry worth over $1 trillion globally. Genetic engineering has gained significant commercial traction because various industries can apply it to increase their productivity and generate revenue.
Even industries where genetic engineering may not seem relevant may demand the complex biological substances that genetic engineering can produce. For example, genetic engineering is being used to develop enzymes and microbiological organisms that can digest oil spills.
The commercial sector is a key driver of innovation in genetic engineering technologies, but governments are also funding and investing in genetic engineering technologies that can provide solutions to health problems, food security, and environmental challenges.
7. Reduced resource consumption
Genetic engineering may develop crops and livestock breeds that demand less water, fertilizer, and feed. Healthier livestock requires less medicine and adding hardiness traits may mean that farmers can rear them in challenging environments that would normally be more resource and labor-intensive.
Enhancing crop yields and animal productivity also means that the resources used for cultivation go further, leading to cost savings for farmers. Consumers benefit from lower prices and foods that may have a longer shelf-life.
8. Eradicating diseases
Genetic engineering is currently being used to develop solutions for eradicating serious parasite-borne diseases like malaria. In sub-Saharan Africa, Asia, and Latin America, malaria is a significant health and economic burden, causing hundreds of thousands of deaths annually.
Genetic engineering that targets mosquitos and the plasmodium parasite that causes malaria could lead to the eradication of this devastating disease. Oxitec, a British company, has already released male GM mosquitoes that carry an inserted gene that encodes a protein which is fatal to their female offspring.
Cons of genetic engineering
Genetic engineering shows a lot of promise, but at what cost should humanity seek to realize its potential? Interference with genes has implications for every living thing on Earth, yet the knowledge and control of these technologies are in the hands of a tiny number of people.
Here are the important downsides of genetic engineering that everyone should know about:
1. The science of genetics is not settled
Genetics is an incredibly expansive area of biology, but it’s important to know that scientists do not fully understand how genes work. Geneticists are continually working in disparate niche areas of this field to contribute to the body of knowledge in this area and regularly publish discoveries that challenge the mainstream understanding of genetics.
Consider this; until recently scientists believed that 99 percent of DNA, which did not code for proteins, was junk. They focused most of the field of genetic engineering on just 1 percent of the total amount of DNA in a cell.
But errors in non-coding DNA have now been implicated in the development of cancers like leukemia and the emerging field of epigenetics has also challenged conventional thinking on the nature and purpose of DNA.
2. Some claims of genetic engineering may be overstated
The promise of genetics as a solution to food shortages and diseases has captured the public imagination. However, the realization of these promises may take many years to achieve, and in some cases, may not be fulfilled at all.
Genetic engineering is still extremely experimental, and for every success reported, there are thousands of failed experiments in the lab. Geneticists work with cells, tissues, enzymes, and proteins that may not always behave as predicted. This means that it can take decades to develop genetic engineering techniques that produce consistent and reliable results.
3. The long-term effects of genetic engineering are unknown
Because genetics is an evolving field, it is impossible to know the long-term effects of gene editing on species, individuals, populations, and the wider environment. This is particularly important for GM crops which may produce harmful protein products that harm wildlife and even accumulate in human tissues causing health problems.
The introduction of GM species into ecosystems may also add novel selection pressure to the environment. GM crop species have out-competed their wild-type equivalents, or transferred their genes to them via hybridization, leading to a loss of biodiversity.
4. Genetic engineering is expensive
Genetic engineering is extremely expensive because of its experimental nature. Gene editing uses some of the world’s most expensive laboratory equipment, reagents, and technical expertise. Genetic engineering routinely takes years of investment before scientists develop commercially viable and safe applications.
This is one of the key limitations of even the most promising gene therapies. Even when a technique is found to work on patients, the costs are so high that few people can access them. Running clinical trials is also very expensive meaning many gene therapies do not obtain the funding to be developed properly.
5. Genetic engineering can lead to unregulated gene expression
Genetic engineering has mastered the technique of inserting a transgene into a host species’ genome, but regulation of the expression of the gene is much more sophisticated. This means that the transgenic organism may over or under-produce the protein product of the inserted gene.
Under-expression of an inserted gene may mean that scientists don’t achieve the desired effect of genetic modification, while over-expression may be harmful to the GMO and animals or people that consume it. In transgenic swine, overexpression of an inserted growth hormone gene resulted in an enlargement of the heart, arthritis, abnormal skeletal growth, and renal disease.
6. Genetic engineering can introduce insertional mutations
By breaking and annealing the ends of DNA with new gene frequencies, geneticists can introduce errors and mutations in DNA that produce disease in the host organism. Insertional mutations may affect the genes that control essential biological processes producing metabolic diseases and cancers.
Worse still, these mutations may be transmissible to subsequent generations, creating new diseases that could be introduced to wild-type organisms through hybridization or mating.
7. Transgene mosaicism or sex linkage may mean that not all offspring carry an inserted gene
Some gene-editing processes are failures, because the GMO does not transmit the inserted gene to all of its offspring.
This is usually because of mosaicism, where only some cells of the organism carry the inserted gene, making its expression inconsistent. Alternatively, in animals or humans, the inserted gene may become sex-chromosome linked (Y-chromosome) so that only males carry the transgene.
8. Genetic engineering requires time and resource-consuming planning to be successful
Genetic engineering projects have to be carefully designed and constructed to achieve the successful insertion of a genetic sequence into a host organism. The high failure rate of these experiments is often because of errors in the inserted gene or its integration site.
Scientists therefore repeatedly model and test the transgene and its insertion site, which can use significant resources and may risk the health and welfare of host organisms.
9. Rogue agents could use genetic engineering for biological warfare or terrorism
Genetic engineering is already being used for controversial ‘gain-of-function’ research, where the genomes of bacteria and viruses are edited to increase their transmissibility or virulence. This research has been taking place in academic settings with the purported objective of investigating pathogens to prevent them from starting pandemics.
Genetic engineering is largely unregulated, with restrictions on access to this technology varying widely between countries. It is not inconceivable that rogue states or nefarious organizations could procure the equipment and expertise to develop bacteria, viruses, or parasites that could infect targeted populations.
10. Genetic engineering could be used for eugenics
Eugenics is an ideology that believes that human reproduction can be controlled to produce populations with pre-determined desirable traits and eliminate individuals with undesirable characteristics. It is a form of scientific racism and has been associated with atrocities and genocides throughout history.
Many advocates of genetic engineering of human beings, point to its potential to ‘improve’ the human race by eradicating genetic abnormalities and introducing desirable traits. Unfortunately, small but powerful groups with little accountability to the wider population may decide what desirable or undesirable hereditable traits are, irrespective of the implications of this course of action.
In the wrong hands, genetic engineering could pursue a eugenics agenda, focused on specific racial groups or populations of people.
11. Genetic engineering enables genes and organisms to be copyrighted
Genetic engineering is a new and fast-evolving area of science and the ethical and legal frameworks that surround it are relatively immature. A key example of this is the patenting of genes and organisms developed through genetic engineering, with companies enforcing ownership of seeds and animal breeds they have developed.
In many jurisdictions, alteration of the genome of an organism makes it a patented product and subject to copyright law. In India, this has been a hotly contested issue, with Monsanto recently winning a Supreme Court case regarding the patents of its GMO cotton seeds.
12. Significant ethical, cultural, and religious concerns surround the use of genetic engineering
Despite its advances and benefits, genetic engineering continues to face deep public antipathy. Many people believe that interfering with genes that are passed from generation to generation is taboo. Even with comprehension of the science and its benefits, they believe that altering living things at a genetic level will harm them.
Religious groups who believe that God created the Earth, perceive generic engineering as a defilement of the Creator’s intelligent design.
With few consistent legal or regulatory boundaries for genetic engineering, ethicists join them in the concern that most people have no say over introducing GMOs into the environment and the genetic engineering of human beings.
As you can see the pros and cons of genetic engineering are a weighty matter, certainly worthy of further investigation. This issue is not only about science but touches on human, animal, and environmental health and welfare ongoing. This means that the evaluation of the societal benefit of genetic engineering should be rigorous with high ethical standards and stringent regulation.