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Altering the genetic structure of organisms is central to modern biotechnology. This article will discuss biotechnology and genetic engineering, offering an overview of the subject.
The Field of Modern Biotechnology: An Overview
Biotechnology is a field that concerns the application of scientific knowledge and engineering to living organisms. The organisms, parts and products of these organisms are used directly or indirectly in their natural or modified form. Biotechnology is a broad field of study used in multiple industries such as medicine, food science, and environmental remediation.
Central techniques of “modern” biotechnology include cell fusion and genetic engineering. Traditional techniques such as selective breeding are also commonly employed in biotechnology, much as they have been for millennia. Recently, genetic engineering has seen increasing use in biotechnology due to advances in knowledge and technology. Many staple foods, for example, are now genetically modified.
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Genetic engineering: an overview
Genome editing of organisms such as plants, animals and microbes has become a hot topic in recent years. The modification of organisms to create favorable traits began around 10,000 years ago. Yet it wasn’t until Gregor Mendel founded the modern field of genetics in the 1800s that the process of transferring genetic information between generations and organisms began to be understood.
In agriculture and food production, desirable traits can be introduced to improve crop yield, disease resistance, nutritional content, and flavor. Individual organisms that express these favorable traits are selected and bred, enhancing the expression of genetic material in subsequent generations. Microorganisms can be genetically engineered to express drugs for the biomedical industry. The modern field of genetic engineering is complex and evolving.
Non-genetic engineering techniques in plants and animals
Before listing some of the genetic engineering techniques commonly used to modify plant and animal species, it is worth exploring non-genetic engineering methods commonly employed in biotechnology. While traditional breeding techniques are increasingly being supplanted by genetic modification, there are still many non-genetic methods of engineering organisms in the food and agricultural industry.
In plants, the simplest technique that has been used since prehistoric times is simple selection. A genetically heterogeneous plant population is inspected and individual organisms that express favorable traits are selected. This makes it easier for these traits to spread and the seeds of these organisms to be planted. Modern technology has improved this method.
An example of modern technology used to improve selection is marker-assisted selection. Molecular analysis detects individual organisms likely to express favorable traits such as increased yield and disease resistance. This method is much faster and more specific than traditional selection. Another modern method of non-genetic engineering is chromosomal engineering, where the chromosomes of close or different species are recombined by chromosomal translocation.
Other non-genetic methods of plant breeding include embryo rescue, somatic hybridization, and induction of mutations through chemical mutagenesis and X-rays. In animals, techniques such as domestication, artificial selection, assisted reproduction and embryo splitting are commonly used.
Genetic engineering in plants
Genetic engineering works by introducing targeted DNA modification into plant cells to produce a favorable trait. Genetic engineering is faster and more specific than traditional methods. Many genetic engineering techniques can adapt plant species to express traits such as increased yield and resistance to environmental stresses and disease. Some of them are listed below.
Microbial vectors are used to introduce genetic material into plants. A commonly used bacterium for this purpose is Agrobacterium tumefaciens which causes crown gall disease. A. tumefaciens is unusual in that it transfers part of its DNA into a host plant upon infection. DNA can be inserted into genetically modified cells A. tumefaciens organisms to introduce new genetic material.
Another process is called microinjection. In this technique, DNA is injected directly into the anchor cells. However, this technique is laborious and inefficient. Electroporation uses an electrical pulse to introduce DNA from a culture medium into plant protoplasts. These can then grow into fully formed plants that incorporate the DNA. Another example of plant genetic engineering uses transposons, short stretches of DNA that can move from place to place in the genome.
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Genetic engineering in animals
Genetic engineering in animals is different from the techniques used for plants. The main technique, although controversial, is cloning. Moreover, animal germ lines can be accessed using several methods such as direct manipulation of fertilized eggs, manipulation of sperm, use of embryonic stem cell lines, and manipulation of cultured somatic cells.
Other ways to genetically modify animal cells include microinjection transfection, electroporation, lipofection, retroviral vectors, transposons, knock-in and knock-out technology, and marker-assisted selection. As genetic engineering is explored more widely for animal species, ethical and safety concerns are proving challenging for the field.
Genetic engineering in microbes
Genetically modified microorganisms are essential for key industries such as medical science, food, biofuel production and environmental remediation. Commercially used microorganisms include bacteria, molds and yeasts. Before the development of molecular genetics, microorganisms were usually modified by ultraviolet and chemical mutagenesis. A natural process still used is conjugation, where genetic material is exchanged between strains.
There are several genetic engineering methods for introducing recombinant DNA into microbes. These include transformation, transduction, and electroporation. Among these methods, transformation is the most commonly used. Electroporation is also widely used in research studies but suffers in effectiveness in many different microbial species. CRISPR-Cas9 has become a leading technology for genetic modification of microbial strains in recent years. Viral vectors and phage libraries are increasingly used.
The future
As scientists continue to reveal more about the genetic code, the opportunities for the fields of biotechnology and genetic engineering are promising. However, there are ethical and safety concerns about the long-term effects of genetic engineering, especially since it is a young discipline. However, the possibilities of the field for several key industries of the 21st century are vast.
