•To study and compare the inherited variations in human DNA without sequencing, a new technique, known as ‘DNA fingerprinting’ was developed by Sir Alec Jeffreys in 1984 at the University of Leicester.
• In DNA fingerprinting, a stretch of mini-satellite DNA known as Variable Number Tandem Repeats (VNTR) tandemly arranged are exploited using the technique, referred to as Restriction Fragment Length Polymorphism (RFLP).
• The process of insertion of a foreign gene (transgene) into the genome of an organism and its transmission and expression in the organism’s progeny is termed as transgenesis. The organisms carrying the transgene are known as transgenic organisms.
• Transgenic plants are also called genetically modified plants, whose genome is modified, like introduction of one or more genes from another species through genetic engineering techniques.
• Basic requirement for genetic transformation is construction of genetic vehicle, which carries the genes of interest flanked by necessary regulating sequences, like promoter or terminator. The most commonly used techniques for gene transfer are of two types: vector-mediated or indirect gene transfer and vector-less or direct gene transfer.
• Vector-mediated or indirect gene transfer includes transformation using Agrobacterium tumefaciens, in planta transformation, plant virus-mediated transfer while vectorless or direct gene transfer includes particle bombardment, protoplast transformation and microinjection.
• Transgenic animals are animals whose genetic makeup has been transformed by the use of various genetic engineering techniques, such as DNA pronuclear microinjection, embryonic stem cell-mediated gene transfer and retrovirusmediated gene transfer.
• Transgenic plants have been developed with improved agronomic traits in crop plants and products, for example, resistance to biotic and abiotic stresses nutrient quality and delayed fruit ripening, etc.
• Transgenic plants are used in Molecular Farming for large scale production of industrial and therapeutic products.
Transgenic animals have also been used in molecular pharming for large scale production of proteins, such as α1-antitrypsin, human α-lactalbumin, etc. Transgenic animals have been developed for use in environment benefits and for research purposes.
• There are a number of concerns related to use of GMOs on human health and environment. The Genetic Engineering Approval Committe (GEAC) established by Ministry of Environment, Forest and Climate Change regulates the manufature, use, import, export of hazardous microorganisums.
• Gene therapy is a technique designed to repair faulty genes in humans by introducing correct genetic material inside cells. There are three main approaches for gene therapy, they are: (i) Gene replacement / Gene addition, (ii) Gene inhibition and (iii) Gene repair/ Gene editing.
• Since, gene therapy includes making changes to the body’s basic set of genes, it raises unique ethical considerations.
• A preparation of killed or weakened pathogen or their components given to elicit an immune response that subsequently recognises the infectious agent and confers protection against disease is known as ‘Vaccine’.
• To avoid several potential concerns raised by conventional vaccines like reversal of the toxoids to their toxigenic forms, or co-purification of undesirable components and to overcome the complexity involved in obtaining sufficient quantities of purified antigenic components, recombinant vaccines were developed using the various tools of rDNA technologies.
• There are three main types of recombinant vaccines: Live genetically modified vaccines, recombinant subunit vaccines and genetic/DNA vaccines
• rDNA technology enables health care by facilitating large scale biological production of a variety of safe, pure and efficient therapeutic agents, such as a Drugs: Monoclonal antibodies, human proteins e.g. Insulin, HGH.
• With the advances in rDNA technology, it is possible to develop mouse antibodies carrying a few human segments known as chimeric or humanised antibodies possessing higher efficacy and activity. • In late 1970s, biochemists exploited various tools of rDNA technology for the production of insulin. They isolated the insulin gene from a gene library and then inserted this gene in a bacterial plasmid of E. coli.
• The first, genetically engineered human insulin marketed as Humulin was manufactured in 1982. Successfulproduction of human insulin proved without any ambiguity, the possibility of genetically engineering diverse biological organisms to produce human proteins for medicinal and therapeutic use.
• DNA technologists can now produce Human Growth Hormone entirely using rDNA technology. In 1985, genetically engineered human growth hormone was produced and marketed as Humatrope and Protropin.
