Genetic engineering involves the
transfer of genes from one organism to an unrelated species. For
example, genetic engineers transfer human genes to the bacteria. Then,
the human DNA in the plasmids of bacteria will continue to produce the
same protein as it did in the human cells. Given suitable nutrients
solutions, the bacteria multiply rapidly and produce vast number of
offspring. The bacteria reproduce by mitosis and so each daughter
bacterium will contain the same DNA and the same plasmids present. The
offspring, therefore, form a clone.
But, before you can insert a segment of DNA
into a bacterium, you will need to extract it from a human cell. And
there is what this chapter is about. The next chapter DNA recombination
will discuss how the wanted gene is inserted into the bacterium.
Generally, there are 3 techniques of
getting a gene. They are cutting them by restriction enzymes, reverse
transcription and De Novo synthesis. We will look at them separately. A
researcher can save the genes in the genomic library and use it
as a resource of other genes of interest or for genome mapping.
In the picture, a gene is been inserted
into a cell.