For a long time, people have been using the traditional breeding techniques such as Artificial selection to obtain the desired characters in the various organisms ranging from ornamental flowers to milk giving animals. In this technique, the organisms having the desired traits are selected and bred to obtain the progeny having the desired qualities of both the parents. But, the problem with this technique is that we have no control over the characters or variations appearing in the progeny. However, with the advancement in the field of biotechnology and genetic engineering, it has become possible to control the characters in an organism right from the gene level. Today, a gene from an organism can be isolated and inserted into an organism of completely different species through the techniques of genetic engineering. The organism resulting from such mechanism is termed as Genetically Modified Organism or GMO.
Cloning and Recombinant DNA technology are the two methods which are widely employed for the development of the GMOs
In the process of cloning, a nucleus is isolated from the cell of the organism to be cloned and is introduced into an enucleated cytoplasm of the host egg cell. This egg cell is then further grown up to 16-32 celled stage and each cell is then transferred into different surrogate mothers. This results in the development of the progeny which is genetically identical to the donor. The first animal to be cloned using this technique was in the year 1996 where a sheep named Dolly was cloned from an adult donor cell. Since that time, a lot of animals have been cloned using this technique such as dogs, horses, cows etc.
In the recombinant DNA technology one or more genes responsible for the specific character are isolated from the organism showing that character, using the restriction enzymes and is then introduced in the host genome using the suitable ligating enzymes. The host cell is then checked for successful transformation and if transformation is successful, multiple clones of the cell are made. BT cotton, golden rice, humulin are some examples which employed this technology for their development.
These techniques have been very useful in the field of agriculture and medicine as they various drought resistant, pest resistant, high nutrition genetically modified crops have been developed. Also many drugs, hormones and enzymes of human use have been manufactured using genetically modified organisms.
Although these techniques are very useful, there are few drawbacks associated with them. Also, the long term effects of GMOs on the naturally occurring organisms haven’t been fully studied yet. Due to these causes the use of GMOs is still controversial and is under debate.