Genetic Engineering Aulanni’amBiochemistry LaboratoryChemistry DepartmentBrawijaya Universityaulani@brawijaya.ac.id
What is genetic engineering? The transfer of genes (segment of DNA) from one species to another. This is impossible in naturally breeding.
How to get the gene from species A to species B? A vector is used to carry the gene into the host nucleus.
What are vectors commonly used in GE? • Plasmid (of bacteria) • Viruses • Shotgun technique (blindly shoots tiny particles coated with the gene into the host cells)
Natural role of a plasmid in bacteria? • Plasmids usually contain one or two gene that confer a selective advantage on the bacterium e.g. antibiotic resistance gene. • Every plasmid possess a replicator gene can duplicated independently from the chromosomal DNA.
1&2 : antibiotic resistance genes 3: replicator gene
Recombinant DNA technology • Cut insulin production gene from a human DNA • Paste it into the DNA of Escherichia coli • The E. coli reproduces rapidly to produce large numbers: gene cloning
restriction enzyme In bacteria, restriction enzymes are found naturally. They cut DNA at specific sites.
Cut insulin gene from human cell (by adding restriction enzyme) Cut plasmid (by adding restriction enzyme) adding ligase enzyme Insulin gene has been inserted into the plasmid
Place the recombinant plasmids back into the bacteria Leave the bacteria to grow and multiply
How do I know which bacteria will have the plasmid? • Add specific antibiotics to the agar culture • All those bacteria which do not have the plasmid will die • Only those with the recombinant plasmids can grow and multiply
Application of GE: • Medical • GM Food • Industrial production • Environmental protection
Medical • Production of pharmaceuticals for treatment of diseases e.g. human insulin, interferons • Production of pharmaceuticals for disease prevention e.g. vaccine (hepatitis B vaccine)
Medical • Gene therapy: Artificially replace the disease-causing gene with a normal allele. The normal allele can be carried by a virus vector to the target tissues. e.g. treatment of cystic fibrosis
Medical • Clonal propagation: a source of tissue or organ for transplantation avoid all problems of immunoincompatibility.
Agricultural • Transgenic plants and farm animals pest-resistant (reduce use of pesticides), increase yield • Increase storage time • e.g. green tomato • tomato with beef genes
Industrial: • Use of GM microorganisms to make stone-wash jeans • Use of GM microorganisms to produce enzymes e.g. detergents
Environmental protection • GM E. coli possesses gene to break down cellulose, speeding up recycling of the most abundant biomass on earth • GM microorganisms with enhanced ability to break down environmental pollutants
Dispute in the development of GM • Dangerous pathogens formed in the course of rDNA • New tools for militarists and terrorists • Triggering of catastrophic ecological imbalance • Moral problems in the use of GM techniques in man e.g. germ cell gene therapy • Unknown effect of GM food on men