12: Modern Applications of Microbial Genetics
Watson and Crick ’s identification of the structure of DNA in 1953 was the seminal event in the field of genetic engineering. Since the 1970s, there has been a veritable explosion in scientists’ ability to manipulate DNA in ways that have revolutionized the fields of biology, medicine, diagnostics, forensics, and industrial manufacturing. Many of the molecular tools discovered in recent decades have been produced using prokaryotic microbes. In this chapter, we will explore some of those tools, especially as they relate to applications in medicine and health care.
As an example, the thermal cycler in Figure \(\PageIndex{1}\) is used to perform a diagnostic technique called the polymerase chain reaction (PCR) , which relies on DNA polymerase enzymes from thermophilic bacteria. Other molecular tools, such as restriction enzymes and plasmids obtained from microorganisms, allow scientists to insert genes from humans or other organisms into microorganisms. The microorganisms are then grown on an industrial scale to synthesize products such as insulin , vaccines, and biodegradable polymers. These are just a few of the numerous applications of microbial genetics that we will explore in this chapter.
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- 12.1: Microbes and the Tools of Genetic Engineering
- The science of using living systems to benefit humankind is called biotechnology. Technically speaking, the domestication of plants and animals through farming and breeding practices is a type of biotechnology. However, in a contemporary sense, we associate biotechnology with the direct alteration of an organism’s genetics to achieve desirable traits through the process of genetic engineering.
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- 12.2: Visualizing and Characterizing DNA
- Finding a gene of interest within a sample requires the use of a single-stranded DNA probe labeled with a molecular beacon (typically radioactivity or fluorescence) that can hybridize with a complementary single-stranded nucleic acid in the sample. Agarose gel electrophoresis allows for the separation of DNA molecules based on size. Restriction fragment length polymorphism (RFLP) analysis allows for the visualization by agarose gel electrophoresis of distinct variants of a DNA sequence.
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- 12.3: Whole Genome Methods and Industrial Applications
- Advances in molecular biology have led to the creation of entirely new fields of science. Among these are fields that study aspects of whole genomes, collectively referred to as whole-genome methods. In this section, we’ll provide a brief overview of the whole-genome fields of genomics, transcriptomics, and proteomics.
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- 12.4: Genetic Engineering - Risks, Benefits, and Perceptions
- Many types of genetic engineering have yielded clear benefits with few apparent risks. However, many emerging applications of genetic engineering are much more controversial, often because their potential benefits are pitted against significant risks, real or perceived. This is certainly the case for gene therapy, a clinical application of genetic engineering that may one day provide a cure for many diseases but is still largely an experimental approach to treatment.
Thumbnail: A group of Genetically modified GloFish fluorescent fish. (www.glofish.com).