Ch 27 Biotechnology Flashcards
Recombinant DNA technology (major steps)
- Obtain a DNA fragment containing the gene of interest
- Obtain a plasmid from a bacterium
- Cut the DNA fragment and the plasmid with the same restriction enzyme
- Join the DNA fragment and the plasmid together using a DNA ligase
DNA fingerprinting (steps)
- Extract DNA: DNA is extracted from the samples of tissues collected. Any tissue of a person can be used as they contain the same DNA. Common sources of DNA: blood, semen, hairs.
- Obtain DNA fragments: DNA fragments containing the selected regions from the DNA sample (highly variable regions) are obtained through proper processes
- Separate DNA fragments: The DNA fragments are separated according to their size using gel electrophoresis
- Produce DNA fingerprints
Why DNA fingerprinting can be used in parentage tests?
Half of the genetic material of an individual comes from the father and the other half from the mother. Half of the bands in the DNA fingerprints of an individual can be found in the DNA fingerprint of the father, and the remaining half can be found in the DNA fingerprint of the mother.
Why the DNA fingerprints of siblings are different?
Due to independent assortment and crossing over of chromosomes, gametes produced from the same person are genetically different. Random fertilization of gametes results in individuals of different genetic composition.
Applications of recombinant DNA technology
- Medicine
- Pharmaceutical products (insulin)
- Gene therapy - Agriculture and food production (increasing productivity / improving nutritional value)
- Industrial uses
- Environmental protection (oil-eating bacteria)
Problems of extracting insulin from pancreas of cattle or sheep
- extraction required long time and was expensive
- only small amounts of insulin were obtained
- may be rejected by the human immune system
- risk of infections
Advantages of producing insulin using recombinant DNA technology
- can be produced in a shorter time
- lower extraction cost
- not rejected by immune system
- low risk of infections
Advantages of producing crops or farm animals using recombinant DNA technology over selective breeding
- quicker
- results are more predictable
- can transfer genes between unrelated species
Gel electrophoresis
DNA fragments are negatively charged due to the phosphate groups present. Under an electric field, they migrate towards the positive terminal. Shorter DNA fragments move faster than longer ones and travel further. DNA fragments are separated into bands according to their size.
Applications of DNA fingerprinting
- Forensic science
- Parentage tests
- Victim identification
- Authentication of foods and Chinese medicines
- Conservation of endangered species
- Tracing the source of infectious diseases
- Screening for genetic diseases
Human Genome Project - Goals
- determine the base sequence that makes up the human genome
- locate all the genes in the human genome
- store the information in a database which is open to the public
- develop related new technologies and improve tools for data analysis
- address the ethical, legal and social issues that may arise
Human Genome Project - Limitations
- functions of many genes are still unknown although the base sequences and locations have been found
- data obtained are still not enough to understand some biological processes
Human Genome Project - Benefits
- better understanding of genetics: how genes control biological processes in the body, how genes are inherited and how genes are mutated, find out the functions of specific genes
- improved diagnoses and treatment of diseases
- better understanding of evolution
