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There are two core techniques that enabled the birth of modern biotechnology:
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- Genetic engineering – Power of DNA Alteration in Biotechnology: These techniques are used to alter the chemistry of genetic material (DNA and RNA), to introduce these into host organisms and thus change the phenotype of the host organism.
- Role of bioprocess engineering in Biotechnology advancements: This technique is used for the maintenance of sterile (microbial contamination-free) ambience in chemical engineering processes to enable the growth of only the desired microbe/eukaryotic cell in large quantities for the manufacture of biotechnological products like antibiotics, vaccines, enzymes, etc.
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What techniques in Genetic Engineering contribute to advancements in Biotechnology?
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- Genetic Engineering Techniques in Biotechnology: It includes the creation of recombinant DNA, the use of gene cloning and gene transfer.
- Advantages of Genetic Engineering: This overcomes the limitations mentioned in traditional hybridisation.
- And allows us to isolate and introduce only one or a set of desirable genes without introducing undesirable genes into the target organism.
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DNA integration and multiplication in Alien organisms:
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- Genetic integration in Alien Organisms: When a piece of DNA is transferred into an alien organism, this piece of DNA would not be able to multiply itself in the progeny cells of the organism.
- But, when it gets integrated into the genome of the recipient, it may multiply and be inherited along with the host DNA.
- Replicating Property: This is because the alien piece of DNA has become part of a chromosome, which has the ability to replicate.
- Significance of Origin Of Replication: In a chromosome, there is a specific DNA sequence called the origin of replication, which is responsible for initiating replication.
- Therefore, for the multiplication of any alien piece of DNA in an organism it needs to be a part of a chromosome(s) which has a specific sequence known as ‘origin of replication’.
- Cloning and DNA Multiplication: Thus, an alien DNA is linked with the origin of replication, so that this alien piece of DNA can replicate and multiply itself in the host organism.
- This can also be called cloning or making multiple identical copies of any template DNA.
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Revolutionizing Genetics: Historic creation of the first Recombinant DNA:
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- It emerged from the possibility of linking a gene encoding antibiotic resistance with a native plasmid (autonomously replicating circular extra-chromosomal DNA) of Salmonella typhimurium.
- Stanley Cohen and Herbert Boyer accomplished this in 1972 by isolating the antibiotic resistance gene by cutting out a piece of DNA from a plasmid which was responsible for conferring antibiotic resistance.
- The cutting of DNA at specific locations became possible with the discovery of the so-called ‘molecular scissors’– restriction enzymes.
- The cut piece of DNA was then linked with the plasmid DNA.
- These plasmid DNA act as vectors to transfer the piece of DNA attached to it.
- A plasmid can be used as a vector to deliver an alien piece of DNA into the host organism.
- The linking of antibiotic-resistance genes with the plasmid vector became possible with the enzyme DNA ligase, which acts on cut DNA molecules and joins their ends.
- This makes a new combination of circular autonomously replicating DNA created in vitro and is known as recombinant DNA.
- When this DNA is transferred into Escherichia coli, a bacterium closely related to Salmonella, it could replicate using the new host’s DNA polymerase enzyme and make multiple copies.
- The ability to multiply copies of antibiotic resistance genes in E. coli was called cloning of antibiotic resistance genes in E. coli.
Hence, there are three basic steps in genetically modifying an organism:
- Identification of DNA with desirable genes;
- Introduction of the identified DNA into the host;
- Maintenance of introduced DNA in the host and transfer of the DNA to its progeny.
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