Biology PRINCIPLES OF BIOTECHNOLOGY

KEY TOPICS

star Introduction to Biotechnology
star Principles of Biotechnology
star Advantages over Conventional Techniques
star Construction of an artificial recombinant DNA molecule

INTRODUCTION TO BIOTECHNOLOGY

● color{Violet}"Biotechnology" deals with techniques of using live organisms or enzymes from organisms to produce products
and processes color{Violet}"useful to humans".

● In this sense, making color{Violet}"curd, bread or wine",which are all microbe-mediated processes, could also be thought as a form of biotechnology.

● However, it is used in a color{Violet}"restricted sense" today, to refer to such of those processes which use color{Violet}"genetically modified organisms" to achieve the same on a larger scale.

● Further, many other color{Violet}"processes/techniques" are also included under biotechnology.

● For example, color{Violet}"in vitro fertilisation" leading to a color{Violet}"test-tube baby" , synthesising a gene and using it, developing a color{Violet}"DNA vaccine" or correcting a defective gene, are all part of biotechnology.

● The color{Violet}"European Federation of Biotechnology (EFB)" has given a definition of biotechnology that encompasses both color{Violet}"traditional" view and color{Violet}"modern" molecular biotechnology.

● color{Brown}"The definition given" color{Brown}"by EFB is as follows":
‘The integration of color{Violet}"natural science" color{Violet}"and organisms", cells, parts thereof, and color{Violet}"molecular analogues" for products and services’.

PRINCIPLES OF BIOTECHNOLOGY

● Among many, the color{Violet}"two core techniques" that enabled birth of modern biotechnology are :

(i) color{Brown}"Genetic engineering" : Techniques to alter the color{Violet}"chemistry of genetic material" (DNA and RNA), to introduce these into host organisms and thus change the color{Violet}"phenotype" of the host organism.

(ii) Maintenance of color{Brown}"sterile" (color{Violet}"microbial contamination-free") color{Brown}"ambience" in color{Brown}"chemical engineering" processes to enable growth of only the desired color{Violet}"microbe/eukaryotic cell" in large quantities for the manufacture of color{Violet}"biotechnological products" like antibiotics, vaccines, enzymes, etc.

● color{Violet}"Traditional hybridisation" procedures used in plant and animal breeding, very often lead to color{Violet}"inclusion and multiplication" of undesirable genes along with the desired genes.

● The techniques of genetic engineering which include creation of color{Violet}"recombinant DNA", use of color{Violet}"gene cloning" and color{Violet}"gene transfer", overcome this limitation and allows us to isolate and introduce only one or a set of color{Violet}"desirable genes" without introducing undesirable genes into the target organism.

● Most likely a piece of DNA, which is somehow transferred into an color{Violet}"alien organism" would not be able to color{Violet}"multiply itself" in the progeny cells of the organism.

● But, when it gets color{Violet}"integrated into the genome" of the recipient, it may color{Violet}"multiply" and be color{Violet}"inherited" along with the host DNA.

● This is because the alien piece of DNA has become color{Violet}"part of a chromosome", which has the ability to replicate.

● In a chromosome there is a color{Violet}"specific DNA sequence" called the color{Brown}"origin of replication", which is responsible for color{Violet}"initiating replication".

● Therefore, for the color{Violet}"multiplication" of any alien piece of DNA in an organism it needs to be a color{Violet}"part of chromosome(s)" which has a specific sequence known as ‘color{Violet}"origin of replication".

● Thus, an alien DNA is linked with the color{Violet}"origin of replication", so that, this alien piece of DNA can color{Violet}"replicate and multiply" itself in the host organism.

● This can also be called as color{Brown}"cloning" or making color{Violet}"multiple identical copies" of any template DNA.

CONSTRUCTION OF AN ARTIFICIAL RECOMBINANT DNA MOLECULE.

● The construction of the color{Violet}"first recombinant DNA" emerged from the possibility of linking a gene encoding antibiotic resistance with a color{Brown}"native plasmid" (autonomously replicating circular extra-chromosomal DNA) of color{Violet}"𝘚𝘢𝘭𝘮𝘰𝘯𝘦𝘭𝘭𝘢 𝘵𝘺𝘱𝘩𝘪𝘮𝘶𝘳𝘪𝘶𝘮".

● color{Brown}"Stanley Cohen" and color{Brown}"Herbert Boyer" accomplished this in 1972 by isolating the color{Violet}"antibiotic resistance gene" by cutting out a piece of DNA from a plasmid which was responsible for color{Violet}"conferring antibiotic resistance".

● The color{Violet}"cutting of DNA" at specific locations became possible with the discovery of the so-called color{Violet}"molecular scissors"– color{Brown}"restriction enzymes".

● The color{Violet}"cut piece" of DNA was then color{Violet}"linked" with the color{Violet}"plasmid DNA".

● These plasmid DNA act as color{Violet}"vectors to transfer" the piece of DNA attached to it.

● In the same way as a color{Violet}"mosquito" acts as an insect vector to transfer the color{Violet}"malarial parasite" into human bod, a color{Violet}"plasmid" can be used as vector to deliver an color{Violet}"alien piece of DNA" into the host organism.

● The color{Violet}"linking" of antibiotic resistance gene with the plasmid vector became possible with the color{Brown}"enzyme DNA ligase", which acts on cut DNA molecules and color{Violet}"joins their ends".

● This makes a color{Violet}"new combination" of color{Violet}"circular autonomously" color{Violet}"replicating DNA" created in vitro and is known as color{Brown}"recombinant DNA".

● When this DNA is transferred into color{Violet}"𝘌𝘴𝘤𝘩𝘦𝘳𝘪𝘤𝘩𝘪𝘢 𝘤𝘰𝘭𝘪", a bacterium closely related to color{Violet}"𝘚𝘢𝘭𝘮𝘰𝘯𝘦𝘭𝘭𝘢", it could replicate using the new color{Violet}"host’s DNA polymeras"e enzyme and make multiple copies.

● The ability to color{Violet}"multiply copies" of antibiotic resistance gene in E. coli was called color{Violet}"cloning of" color{Violet}"antibiotic resistance" gene in E. coli.

● Thus it can be inferred that there are color{Violet}"three basic steps" in genetically modifying an organism —

(i) color{Violet}"Identification" of DNA with desirable genes;

(ii) color{Violet}"Introduction" of the identified DNA into the host;

(iii) color{Violet}"Maintenance" of introduced DNA in the host and transfer of the DNA to its progeny.