Genetic Engineering

GENETIC ENGINEERING

At the end of this lesson you should be able to:
1. Define Genetic Engineering
2. Outline the process of genetic engineering involving some or all of the following:
  - Isolation
  - Cutting
  - Transformation
  - Introduction of base sequence changes
  - Expression
3. Know three applications: one plant, one animal, one micro-organism

Genetic Engineering is described as:
- The simple addition, deletion, or manipulation of a single trait in an organism to create a desired change.
- It involves the manipulation and alteration of genes.
- It is defined as artificially copying a piece of DNA from one organism and joining this copy into the DNA of another organism.

Allows genes from one organism to be inserted into a cell of a different organism of a different species.
Examples of gene insertion:
- Human genes can be inserted into a bacterium.
- Human genes can be inserted into cells from other animals.
- Bacterium genes can be inserted into plant cells.

Transgenic Organisms:
- Organisms altered by genetic engineering.
- Genetic material changed by means other than random natural breeding.
- This process involves gene transfer, which is the movement of a gene from one organism to another.
Meaning of Transgenic:
- '-Trans-' refers to 'crossing from one place to another'.
- 'Genic' refers to genes.
- Thus, transgenic means that bits of genes from different living things have been combined and spliced into another organism to create a new organism with desired traits.

GMO (Genetically Modified Organism)
GEO (Genetically Enhanced Organism)
- Example 1: Plants that resist a particular type of weed killer.
- Example 2: Sheep that produce special substances in their milk.

Isolation Process:
- Isolation of a specific gene from a donor (e.g., human):
  - Cells are broken open.
  - A genetic probe is added, revealing the position of the gene of interest.
- Isolation of Plasmid from a bacterial cell:
  - Involves extracting the plasmid, which is a circular DNA found in bacterial cells, alongside the bacterial chromosome.

Restriction Enzymes:
- Act as molecular scissors that cut DNA at specific sites known as restriction sites, which allows for specific DNA fragments to be isolated and manipulated.
- The process includes creating sticky ends for easier joining of DNA segments:
  - Example sequence:
  - ( ext{C-T-C-G-A-T-G}) \
  - ( ext{G-A-G-C-T-A-C-T})
  - Sticky ends facilitate the joining process in subsequent stages.

Ligation refers to the rejoining of cut fragments of DNA to form artificial recombinant molecules with the help of DNA ligase.
- Hybrid plasmids are formed, which consist of the plasmid and the foreign DNA segment.

In this stage, the recombinant DNA is introduced into the bacterial cell, resulting in a colonized cell capable of reproducing the donor gene.

The bacterial cell reproduces by binary fission, producing the polypeptide coded for by the donor DNA.
Expression is the mechanism whereby an organism with recombinant DNA produces the desired protein, which must then be isolated and purified when produced in significant quantities.

The human gene responsible for blood clotting has been inserted into the DNA of sheep, allowing the sheep to produce human clotting factor in their milk.
Goats can also produce a protein aimed at treating emphysema.

Humulin: A form of recombinant DNA used in diabetes management, produced by modified bacteria; prevents allergic reactions to animal insulin.

Golden Rice is engineered to address Vitamin A deficiency, potentially preventing blindness.
Crops engineered to be resistant to specific weed killers, ensuring survival amidst agricultural challenges.

Refers to a genetic engineering application to alter an animal's DNA (by introducing new DNA, termed a transgene) for medical protein production.
- Genetically modified animals are utilized to produce medicinal proteins that are collected for therapeutic use.

Tracy was one of the first mammals successfully engineered for pharming, born in 1990, producing large quantities of the human enzyme alpha-1 antitrypsin in her milk to treat conditions such as cystic fibrosis and emphysema.

Involves the transplantation of living cells, tissues, or organs from one species to another.
Ethical considerations and receptiveness issues arise, along with the potential for viral transmission, especially in studies involving porcine islet transplants for type 1 diabetes.

A method involved in repairing or replacing faulty human DNA to combat genetic diseases, such as cystic fibrosis, which has been the focal point of gene therapy trials.

Genetic engineering enables the creation of specific and sensitive diagnostic tests for various diseases using engineered proteins, which also opens up new avenues for delivering medicines to targeted areas.

Genetically engineered microbes can produce the necessary antigens in a controllable and safe manner. Notable success includes the use of genetically modified yeast cells for producing vaccines against the hepatitis B virus.

A comprehensive understanding will reflect an outlook on its applications in various fields such as medicine (diabetics, treatment of genetic disorders), agriculture (modifying food sources), and bioprocessing (creating enzymes or proteins), encapsulating the transformative potential of genetic engineering.