Genetic engineering is the artificial manipulation, modification, and recombination of DNA or other nucleic acid molecules in order to modify an organism or population of organisms. The term genetic “engineering” is generally used to refer to methods of recombinant DNA technology, which emerged from basic research in microbial genetics. The techniques employed in genetic engineering have led to the production of medically evolved products, including human insulin, human growth hormone, and hepatitis B vaccine, as well as the development of genetically modified organisms such as disease-resistant plants.
The potential public health benefits of genetic engineering are immense, but there are potential harms as well. Genetic engineering may help to promote health and prevent illness by increasing the quality and quantity of food, cleaning up toxic environments, and reducing human health problems for existing and subsequent generations.
Genetic engineering might also threaten human health, by producing unsafe foods, polluting the environment, and otherwise undermining or compromising the health status.
How Genetic engineering impacts our everyday lives
Genetic engineering has advanced the understanding of many theoretical and practical aspects of gene function and organisation. Through recombinant DNA techniques, bacteria have been created that are capable of synthesising human insulin, human growth hormone, alpha interferon, a hepatitis B vaccine, and other medically useful substances. Plants may be genetically adjusted to enable them to fix nitrogen, and genetic diseases can possibly be corrected by replacing dysfunctional genes with normally functioning genes. Genes for toxins that kill insects have been introduced into several species of plants. Bacterial genes that bestow resistance to herbicides also have been introduced into crop plants. Other attempts at the genetic engineering of plants have been aimed at improving the nutritional value of the plant.
Application of genetic engineering in the food industry
Genetic engineering finds major application in the food industry due to modification of the genetic material of plants or animals. Many genetically modified whole foods or ingredients present in the food industry available today are a result of gene modification.
In general, several enzymes are involved in the fermentation and digestion of foods. This has led to the concept of production of recombinant enzymes from genetically modified microbes such as chymosin and lipase for cheese production, and alpha-amylase for flavour enhancement in the beer industry. A mixture of enzymes called Rennet is used to coagulate milk into cheese. This specific enzyme was initially available from the stomach of calves, and or from microbial sources – thus it was expensive and caused unpleasant tastes. Genetic engineering has succeeded in isolating and cloning rennet-producing genes from animals into bacteria, fungi or yeasts to produce chymosin-a key enzyme present in rennet. Several organisms like E. coli, Kluyveromyces lactis, and Aspergillus niger are cloned to produce recombinant chymosin. One of the latest technologies involves the production of cow milk containing increased amounts of cheese making protein, casein and foods without beta-lactoglobulin (an allergen in milk) by RNA interference Technology.
Genetically modified foods are obtained from genetically modified organisms, or “transgenic crops”. Genetic engineering has resulted in a number of improved traits in transgenic plants by genetic alteration. Some of these traits are:
- Production of extra nutrients in the food
- Increased growth rate
- Disease resistance
- Herbicide resistance
- Enhanced taste
- Increased shelf life
- Lesser requirement for water
Application of genetic engineering in the pharmaceutical industry and medicine
Through genetic engineering, a variety of medical products are available today. Among these products, insulin and human growth hormone were the first commercially available products obtained from recombinant E. coli. Recombinant insulin is the result of successful genetic engineering. It is now commercially available in several forms and is involved in diabetes Therapy.
The production of pharmaceutical products from transgenic animals is called “Pharming”. Pharming involves the use of genetic engineering techniques. The recombinant proteins produced by pharming act as drugs for various human diseases. These therapeutic products can be directly injected into the bodies of the patient to treat the disease and cure deficiencies. Recombinant vaccines are an important group of therapeutic products. A number of vaccines are now available for animals and humans which are going to have a major impact on the healthcare industry. One of the initial vaccines produced by rDNA method involves the cloning of the surface antigen of the hepatitis B virus (HBsAg) in the yeast S. cerevisiae under the control of the alcohol dehydrogenase promoter. A number of recombinant vaccines are now commercially prepared by the recombinant DNA technology, where only the outside coat protein of the microorganism is expressed in the host to create the vaccine. The expressed protein can then be purified from the recombinant host and used for inoculation. This method has the advantage of safe delivery of antigen without transferring the actual disease-causing microbe to the host. Currently, recombinant vaccines for the hepatitis B virus, herpes type 2 viruses, and malaria are under trial for use in the future.
The latest development involves the production of edible vaccines using transgenic plants as a delivery mechanism, which involves the presence of vaccines in the edible part of the plant. This technology has tremendous potential as it enables easy delivery of vaccines by mere consumption of the edible part. The trials for the development of a vaccine-containing banana or tomato are currently underway. With the advancement of genetic engineering, it would be possible to treat genetic defects by the replacement of the defective gene with a functional copy by gene therapy. This technique has great potential in the treatment of genetic diseases.
The gene therapy protocol can be made effective by the following approaches:
- Insertion of a normal gene to compensate for a nonfunctional gene
- Repair of an abnormal gene by selective reverse mutation
- Alteration in the regulation of gene pairs
Several genetic disorders caused by single-gene defects, such as cystic fibrosis, muscular dystrophy, haemophilia, sickle cell anaemia and AIDS can be treated by gene therapy approach for which clinical trials are in process.
Application of genetic engineering in the Environment
Genetic engineering is exploiting the huge potential of microorganisms, plants, and animals for the restoration of the environment. Genetic engineering is actively involved in the development of microorganisms and biocatalysts for remediation of contaminated environments, and in the development of eco-friendly processes such as developing recombinant strains for biofuel production etc.
Several genetically engineered microorganisms (GEMs) are developed which are involved in the biodegradation of waste materials. As the genes for enzymes involved in the bio-degradation pathway are mainly located on the plasmids, it is possible to create new strains by genetic manipulations of such plasmids. Using this technique, a new strain of bacterium Pseudomonas was developed and named as “Superbug”. This superbug is able to produce a combination of enzymes involved in the degradation of several hydrocarbons present in petroleum.
Genetically modified organisms are used in clearing up oil spills which are a major environmental hazard. New strains of Pseudomonas have been developed to break down a variety of hydrocarbons present at the oil-spill site, thus decreasing the use of toxic chemical dispersants. Some microorganisms which are involved in the degradation of hydrocarbons are pseudomonads, corynebacteria and some yeasts.
Increased use of herbicides, pesticides and insecticides causes the problem of soil pollution. The overuse of chemical herbicides, pesticides and fertilisers is detrimental to the environment. That can also be solved by using recombinant microorganisms. An attempt is being made to develop bacterial and viral pesticides which will help in reducing the use of chemical pesticides. Genetically engineered bacteria in which toxic genes from Bacillus thuringiensis are cloned and are used as biological pesticides.
Application of genetic engineering in Crop improvement through Transgenesis
Crop plants have been the focus of genetic engineering as efforts are being made to improve their traits of plants. Transgenic plants are developed for the following reasons:
- Gene insertion may result in improvement in the agricultural or commercial value of a plant.
- Transgenic plants can act as living bioreactors facilitating the production of commercially important proteins or metabolites.
- Transgenic plants help in the understanding of the function of different genes.
A number of genes can be combined with crops to produce desirable properties such as:
- Herbicide- drought, freeze- or disease-resistance
- Higher yield-; Tolerance toward cold, drought, salt
- Faster growth;
- Improved nutrition
- Delay of senescence
- Longer shelf life
- Increased post-harvest shelf life
- Altered flower pigmentation
- Nitrogen fixation Capacity to fix atmospheric nitrogen
Transgenic plants can be designed to produce a variety of useful compounds, like therapeutic products and metabolites. Recently transgenic crops with combined traits like herbicide tolerant and insect resistance have been developed. Genetically Modified plant products in the pipeline are:
- Increased levels of iron and vitamin A in rice.
- Fast ripening process in banana
- Improved feed value in maize
- High levels of flavonols in tomatoes
- Drought tolerance in maize
- Increased phosphorus availability in maize
- Plants more tolerant to arsenic
- Edible vaccines from plants
- Low lignin content in trees
- “Glowing plant” with a gene from firefly that glows in the dark
Application in trait improvement of animals through transgenesis
Genetic engineering involves the introduction of a transgene into animals to improve the trait of
transgenic animals. Transgenic animals finally express the trait of the introduced gene. Transgenic animals are also created to study the function of different genes to develop proper treatment of a disease.
Transgenic animals can be a successful means to provide an economical production of enzymes, proteins, quality and quantity improvement of meat and other animal products. Since the successful cloning of Dolly, a sheep by genetic engineering, there has been a continuous effort in the direction of cloning useful livestock.
Some of the remarkable products developed through transgenesis in animals include:
- Production of human proteins in animal milk
- Production of BioSteel, a high-strength silk product, from goat’s milk
- The growth of tissues on 3-D printers by genetic manipulation of stem cells can be used as a skin substitute for wound healing.
- Production of therapeutic proteins, such as monoclonal antibodies, from the milk of transgenic cows, goats, and mice, which is used to administer drugs in various diseases.
Prospects of Genetic Engineering
Genetic engineering and transgenesis thus hold tremendous potential in the field of basic research and also commercial and industrial consideration of different products.
In recent years one of the most important developments in genetic engineering involves a new gene-splicing technique called “clustered regularly interspaced short palindromic repeats” – known by its acronym, CRISPR. This new method greatly improves scientists’ ability to accurately and efficiently “edit” the human genome, in both embryos and adults. The development of CRISPR-Cas proteins for genome editing applications now has had a profound impact on biology and biotechnology over the past few years. These tools have democratised the ability to rewrite the information contained in genomes and thereby to both understand and alter genetic traits. It is believed that CRISPR technology would positively change the lives of millions of people. Over the next decade, researchers would continue to advance the use of CRISPR-based tools to treat and in some cases cure diseases, develop more nutritious crops, and eradicate infectious diseases. It is a profoundly powerful technology, but one must be mindful of potential unintended or undesirable consequences and apply it responsibly.
The responsible and ethical application of the latest genome editing tools is to work toward curing patients who suffer debilitating genetic diseases. This endeavour would demand the cooperation of researchers across government, academic, and industrial sectors, working together in a spirit of transparency and a common desire to propel cutting-edge science forward in order to both advance the field and make an impact on human health and genetic disease. As with any bold challenge, cross-sector collaboration, informational transparency, honest dialogue, and a commitment to scientific excellence and integrity are essential while treating genetic diseases through the modification of a patient’s DNA. If dealt with responsibly, genetic engineering would have an immense impact on the lives of people in the coming decades.
How genetic engineering will reshape humanity in the coming decades
New genetic technologies are exhilarating but can be terrifying as well. Society might overcome diseases by tweaking individual genomes or selecting specific embryos to avoid health problems. But it might also give rise to “superhumans” who are optimised for certain characteristics like intelligence, power or looks and exacerbate inequalities in society.
The impact of this transformation is being first experienced in the healthcare industry. Gene therapies including those extracting, re-engineering, and then reintroducing a person’s own cells enhanced into cancer-fighting supercells are already performing miracles in clinical trials. Thousands of applications have already been submitted to regulators across the globe for trials using gene therapies to address a host of other diseases. The progress of genetic engineering would ensure that millions and then billions of people would have their genomes sequenced as the foundation of their treatment. Big data analytics will then be used to compare at scale people’s genotypes to their phenotypes.
These massive data sets of genetic and life information would then make it possible to go far beyond the simple genetic analysis of today and to understand far more complex human diseases and traits influenced by hundreds or thousands of genes. The understanding of the complex genetic system within the vast ecosystem of our bodies and the environment around us would transform healthcare for the better and help cure terrible diseases that have plagued our earlier generations for millennia.
The most profound application of genetic engineering would be in future baby-making. Before making a decision about which of the fertilised eggs to the implant, women undergoing in vitro fertilisation would elect to have a small number of cells extracted from their pre-implanted embryos and sequenced. With current technology, this can be used to screen for single-gene mutation diseases and other relatively simple disorders. Polygenic scoring would soon make it possible to screen these early-stage pre-implanted embryos to assess their risk of complex genetic diseases and even to make predictions about the heritable parts of complex human traits.
The overlapping of genomics and AI revolutions are expected to happen far sooner than most people recognize.
Current scientific advancements show that CRISPR is not only an extremely versatile technology, but it is also proving to be precise and increasingly safe to use. Though a lot of progress still has to be made.
Technological and ethical hurdles still stand between the current world and a future in which the planet would be fed with engineered food, eliminate genetic disorders, or bring extinct animal species back to life. Technological advancements are well on the way to progress and with proper planning and implementation, a brighter and advanced future awaits for sure.
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