Gene Technology

DNA is created by combining two or more DNA molecules from different origins.

Genetic engineering involves modifying the genetic material of an organism to manipulate a characteristic in the host organism. It is achieved by deleting, substituting or inserting DNA fragments at specific locations in the host organism’s genome.

1. The gene that encodes the desired product (e.g., protein) must be isolated. This process involves producing DNA fragments that contain the desirable gene.

2. The gene then needs to be inserted into a vector. Vectors are carriers for delivering foreign genetic material, such as a functional gene, directly into a cell.

3. The vector delivers the gene to the recipient cells. This delivery process is called transformation.

   Transformation describes the cell's genetic modification via direct uptake and inclusion of foreign genetic materials from its surroundings.

4. The recombinant cells that have successfully transformed and now contain the recombinant DNA need to be identified. Marker genes, such as antibiotic resistance genes, assist in this step.

5. Following identification, the recombinant cells are cloned to produce a large population of transgenic cells.

1. Using reverse transcriptase to convert mRNA to cDNA (coding DNA). 
2. Using restriction endonuclease to cut the DNA molecule at a specific sequence.
3. Using a gene machine to create a gene based on a protein with known structure and composition.

PCR is an in vitro method of copying and amplifying a DNA segment. It is also used for creating many double-stranded copies of a single-stranded DNA fragment.

Large amounts of mRNA in a cell that is actively transcribing the gene. The mRNA can be extracted to make cDNA. cDNA produced is intron free.

More steps are involved. It is time-consuming. It requires more technical expertise.

Sticky staggered ends on DNA fragments make DNA ligation and recombinant DNA production easier.

The fragments created may contain introns and thus may not be usable in prokaryotic systems.

The exact DNA fragment can be designed with custom sequences. The fragments can be designed to contain markers and sticky ends.

Palindromic

retroviruses such as HIV; DNA strands; mRNA

The organism that contains this recombinant DNA is a transgenic or a genetically modified organism (GMO) which can be as simple as bacteria or as complex as plants and animals.

• Allows for creating more nutritious foods to eradicate malnutrition around the world.
• Disease and drought resistant plants allow for the use of fewer environmental resources.
• Increased food supply with lower cost.
• Increased shelf life of certain rootstock.
• Greater yields in farming crops for making biofuels.
• Faster growing crops and animals.

• The food produced from GMO animals can have less nutritional value due to a faster rate of development.
• Introducing new genetic material into nature can result in new resistant pathogens that are stronger and pose a health risk.
• There can be adverse side effects that are unknown and unexpected.
• Many companies place copyright over the GMOs they develop. It can have costly consequences for the farmers since they would have to pay greater GMO seeds.
• Abuse of genetic engineering technology and knowledge on animals and humans can lead to ethically questionable outcomes.

Requires the amino acid sequence of the desired protein.

In vivo is Latin for ‘within the living.’ It involves transferring the gene into a host cell using a vector to make many copies of the gene.

In vitro is Latin for ‘in the glass.’ It involves using the polymerase chain reaction (PCR) in the lab.

Restriction sites

They have a palindromic sequence.

The single-stranded part of any of the DNA fragments can join the single-stranded part of any other DNA fragment hence causing the ends to be sticky.

In both eukaryotic and prokaryotic systems, RNA polymerase initially binds to regulatory regions of the DNA called the promoter which is adjacent to the gene.

The region of DNA after the gene where the RNA polymerase dissociates.

A vector is any carrier, usually a virus or plasmid, that is used to transport a desired piece of DNA into a host cell.

Transformation involves the introduction of recombinant DNA into the host cells. It requires calcium ions and a change in temperature.

Ampicillin and tetracycline

Antibiotic resistance genes, fluorescence markers, and enzyme markers.

Green fluorescent protein is a fluorescence marker first identified in jellyfish.

DNA ligase

Lactase converts a colourless substrate to blue.

polymerase chain reaction

It makes copies of a specific DNA fragment outside of living systems (in vitro).

Taq DNA polymerase

Taq DNA polymerase works best at relatively high temperatures such as 72C. This allows for faster replication of DNA.

Primers are fragments composed of 18-30 nucleotides that are complement the beginnings of each of the two DNA strands at either end.

 Primers bind to the beginnings of the two DNA strands and allow the recruitment of Taq polymerase.

An instrument that automatically increases and lowers the temperature of samples in a closed container according to a program.

True

False

True

True

False

Cystic fibrosis and severe combined immunodeficiency (SCID).

• Bacteria may be genetically engineered to generate a variety of compounds such as antibiotics, hormones, and enzymes used to treat illnesses and disorders.
• Genetically modified crops can also be made tolerant against pesticides and herbicides. This increases the cultivation yield and hence reduces the price of food.
• Certain genetic illnesses, such as cystic fibrosis (CF) and severe combined immunodeficiency (SCID), may be cured by replacing faulty genes. This treatment is called gene therapy.
• Microorganisms can be utilised to reduce pollution. They can be modified to break down and digest oil slicks to remove toxic gases emitted by companies.
• Transgenic crops can be designed to be more resistant to environmental extremes, such as drought, cold, heat, salt, or contaminated soils. This allows crops to be cultivated economically in areas where they do not naturally grow.

• Antibiotic resistance marker genes are often introduced to genetically engineered bacteria which are used for identifying successfully transformed recombinant cells. These bacteria have the potential to transfer their antibiotic resistance genes to dangerous pathogenic microbes.
• We are uncertain of what long term consequences gene editing and introducing new genetic material into nature can have on the ecosystem both on a micro and macro level.
• The ability to manipulate and exchange faulty genes brings on ethical questions on where the line should be drawn. Treating cystic fibrosis by gene editing is acceptable but what about changing one’s features, such as eye colour, muscle tone or intelligence?

DNA probes are short pieces of single stranded DNA that are labelled so that they are easily identifiable.

DNA hybridisation describes the combination of a section of DNA or RNA with a single stranded piece of DNA probe that contains complementary sequences and is labelled to ease its detection.

Radiolabelling with radioactive phosphorous or labelling with a fluorescent dye

To break the hydrogen bonds between strands and separate the DNA strands from each other.