Genetic Engineering

  • is a process that involves modifying the genome of an organism to introduce desirable characteristics

  • Specifically, genetic engineering is changing the genetic material of an organism by removing or altering genes within that organism, or by inserting genes from another organism


  • The organism receiving the genetic material is said to be genetically modified or is described as being a transgenic organism

  • The DNA of the organism that now contains DNA from another organism as well is known as recombinant DNA

  • There are many examples of genetically modified organisms, including:

    • The gene for human insulin has been inserted into bacteria, which then produce human insulin that can be collected and purified for medical use for diabetics

    • Crop plants, such as wheat and maize, have been genetically modified to contain a gene from a bacterium that produces a poison that kills insects, making them resistant to insect pests


Genetic engineering in medicine

  • Modern medical research is exploring the possibility of genetic modification to overcome some inherited disorders

  • As these inherited genetic diseases are caused by faulty genes, it may be possible to treat these by inserting working versions of these genes into people with the genetic disease

  • This is called gene therapy


Process of Genetic Engineering - practical/6 markers

1) Identify the gene: Desired gene that’s to be inserted is located in the original organism (e.g human insulin gene)

2) Extract the gene: Genes from chromosomes are cut out using restriction enzymes to isolate the required gene to leave a short section of unpaired bases known as “sticky ends”

3) Join the DNA: A bacterial plasmid is cut by the same restriction enzyme leaving it with corresponding sticky ends (plasmids are circles of DNA found inside bacterial cells)& the plasmid and the isolated gene are joined together by DNA ligase enzyme

4) Transform host: Insert the recombinant plasmid into host cells (like bacteria).

5) Select cells: Identify and select the successfully modified cells using antibiotic marker genes.

6) Replicate and express: Grow the bacteria in a fermenter so they replicate and express the gene to produce the desired protein (e.g., insulin).