Transcript Chapter 9 Biotechnology

Chapter 9
Genetic engineering
• Deliberate manipulation of genes in an
organism.
• Done in a lab by scientists
• Therapeutic substances such as human
insulin.
• Insulin came from pancreas obtained from
slaughtered animals
• Genetically engineered E.coli cells to
make human insulin
Tools used in genetic engineering
Restriction enzymes
• Bacteria – restriction enzymes
• To breakdown phage DNA
• Extract the restriction enzyme from
bacteria and use it genetic engineering
• EcoRI, BamHI – recognize specific
sequence
• Staggered cuts on DNA
• Ends of the fragment are single stranded
Sticky ends
Cohesive ends
ligase
• Vectors – carry the gene of interest into a
bacterial cell.
• Plasmids
• Small enough – they can enter into the cell
• Selection markers – antibiotic resistance
genes.
• Help in selecting the cells that have the
gene of interest.
Gene library
•
•
•
•
•
Collection of genes from an organism
Mouse gene library, yeast gene library
Biotechnology company
Yeast gene library
DNA – fragment – restriction enzyme –
fragments are inserted into plasmids –
introduced into a bacterial cell
• Each bacterial cell having the recombinant cell is
a clone
• Large # clones – a clone for each gene that
exists in the yeast cell
Hexokinase
Malate
Dehydrogebase
pheromone
Helps the cells
To come together
And mate
cDNA
•
•
•
•
•
•
Complementary DNA
Eukaryotic genes – introns and exons
Introns – noncoding regions
Exons - coding regions
cDNA – synthetic gene – has only exons
c stands for complementary DNA
• If we want to introduce eukaryotic gene
into a prokaryotic cell, we should use
cDNA
• If we place natural eukaryotic gene into a
• Bacterial cell, it cannot remove the introns.
• Functional protein will not be produced by
the prokaryotic cell.
Applications of genetic engineering
• Hormones – insulin
• Growth hormone – somatotorpin
• Produced by genetically engineered E.coli
cells.
• Treat stunted growth
• Pituitary gland removed during autopsy.
vaccine
• Hepatitis B vaccine
• Genetically engineered Saccharomyces
cells
• Vaccine has only the protein part of the
virus.
• Does not have the genetic material of the
virus
• No chance of getting the disease due to
vaccination
Genetic screening
• Carrier of genetic disorder
• Cystic fibrosis genetic disorder
• Mutation in a gene that codes for a
membrane protein.
• Protein is not functional
• Produce thick mucus blocks airways and
causes various health problems.
• Person has the disease – symptoms
• Some people are carriers
• One cystic fibrosis gene (father) one
normal gene (mother) – heterozygous for
cystic fibrosis
• Two carriers – have a baby – the baby can
have the disease
• Genetic screening is used – procedure
known as southern blotting.
Gel electrophoresis
Single stranded
DNA complementary
hybridize
Agriculture
Forensic medicine
Each person has a
unique set of introns.
restriction enzyme
fragment pattern of DNA
Polymerase
Chain
Reaction
Amplify DNA
Target DNA
Nucleotides
DNA polymerase