● `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’.

● 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.

● 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.