**1. Introduction**

Genetic engineering refers to the process of altering the genetic code of any living organisms by transferring the genes from one organism to the chromosome of another in such a way that its biosynthetic properties get modified. The manipulation of genetic material or genes is carried out using selective breeding or through molecular biological techniques [1]. This process alters the biological capabilities of an organism, and it can be utilized for the industrial production of desired proteins, enzymes, antibiotics, agricultural products, etc. [2, 3]. Genetic engineering allows us to develop crops with agronomically beneficial changes like resistance to pests and harsh environment and enhanced productivity with lesser ripening time [4]. Apart from other agricultural applications, genetic engineering can also be advantageous in curing human disease [5].

Genetic engineering can also be referred to as the mechanism of changing the level of protein expression. In a condition where a large amount of protein is required for the purpose of purification, its level of expression can be altered by changing its promoter [6, 7]. Hence, the term "genetic engineering" can also be

referred to as "protein engineering" since the biochemical properties of a protein are changed through gene mutation or in vivo alteration of genes [8].

The technique of genetic engineering has evolved through our context of understanding genetics.

The methodology of manipulation of genetic material was developed in the 1970s. In vitro, the DNA was altered in a test tube and later introduced within the living cell thus altering the life process of the organism [9].

The current chapter debriefs about the outline of the genetic engineering process and its application in various fields.
