Learning Outcomes

• define the term recombinant DNA

• explain that genetic engineering is the deliberate manipulation of genetic material to modify specific characteristics of an organism and that this may involve transferring a gene into an organism so that the gene is expressed 

• explain that genes to be transferred into an organism may be: 

  • extracted from the DNA of a donor organism 

  • synthesised from the mRNA of a donor organism

  • synthesised chemically from nucleotides 

What is Genetic Engineering?

• The process of removing a gene (or genes) from one organism and transferring it into another.

• The goal is for the transferred gene to be expressed in the recipient organism.

Key Terms

Recombinant DNA (rDNA)

DNA that has been altered and now contains nucleotide sequences from two different organisms.

Key Terms

Transgenic Organism / Genetically Modified Organism (GMO)

An organism that expresses a new gene or genes introduced through genetic engineering. The introduced DNA can come from another species or even an organism from a different domain (e.g., bacteria to plant).

Genetic engineering

• Allows us to overcome the natural barriers that prevent gene transfer between different species.

• For examples: Inserting a bacterial gene into a plant or a human gene into a bacterium.

Precision vs. Traditional Breeding:

• Unlike selective breeding, which involves the manipulation of whole sets of genes, genetic engineering often focuses on the transfer of a single, specific gene.

• This allows for more targeted and precise modifications to an organism's traits.

Creating a Genetically Modified Organism (GMO) involves a series of crucial steps to successfully introduce and express a new gene.

The Steps of Gene Transfer in GMO Production

The desired gene is identified and obtained.
This can be done by:

• Cutting it from a chromosome.

• Synthesizing it from mRNA using reverse transcription.

• Directly synthesizing it from nucleotides.

​​Gene Identification and Isolation

Multiple copies of the isolated gene are created using the Polymerase Chain Reaction (PCR) technique.

Gene Amplification

The gene is inserted into a vector, which acts as a delivery vehicle to introduce the gene into the recipient organism's cells.

Vector Insersion

• Plasmids (small circular DNA in bacteria)

• Viruses

• Liposomes (lipid vesicles)

Examples of vectors include

The vector carrying the gene is introduced into the cells of the target organism.

Gene Delivery

Cells that have successfully taken up and integrated the new gene are identified, often using marker genes. These successful cells are then grown and cloned to produce organisms with the desired genetic modification.

Cell Selection and Cloning

Genetic Engineering Toolkit

Such as restriction endonucleases (for cutting DNA), DNA ligases (for joining DNA fragments), and reverse transcriptase (for creating DNA from RNA).

Enzymes

Including plasmids and viruses, to carry the desired gene.

Vectors

Genes coding for easily identifiable substances, allowing for the selection of cells that have taken up the new gene.

Marker Genes