Unit 4, Topic 5 - Genetic Engineering Code of Life Topic 5 Genetic analyses & Genetic Engineering

Genetic analyses & engineering What are these? What are the uses? What do they start with? Genetic engineering applications DNA “fingerprinting” Uses Technology (third quarter lab!) Genetic testing and related ethical concerns

Unit 4, Topic 5 - Genetic Engineering Isolating the gene Use special proteins to cut the DNA strand at specific places Restriction enzymes: Target very specific base sequences Are found in more than 100 different varieties Are used in nature to protect bacteria from foreign invaders

Unit 4, Topic 5 - Genetic Engineering Restriction Enzymes Each restriction enzyme recognizes a very specific nucleotide sequence EcoR1 recognizes: GAATTC CTTAAG The enzyme cuts it: G AATTC CTTAA G

Unit 4, Topic 5 - Genetic Engineering

Which DNA segments are used? Unit 4, Topic 5 - Genetic Engineering Which DNA segments are used? Short tandem repeats (STRs) are short sequences repeated multiple times in a row (more or less for different people) Good for “fingerprinting”: A total of 13 different STR sites is enough for an individual profile

Which DNA segments are used? Unit 4, Topic 5 - Genetic Engineering Single nucleotide polymorphisms (SNPs) are single base-pair variations that we can detect (like a substitution mutation) Scientists have a catalog of SNPs that occur in the human population. Restriction fragment length polymorphisms (RFLPs) are SNPs that change the length of restriction fragments

Which DNA segments are used? Unit 4, Topic 5 - Genetic Engineering Which DNA segments are used? Restriction Fragment Length Polymorphisms (RFLPs)

Analyzing the differences between people Unit 4, Topic 5 - Genetic Engineering Analyzing the differences between people Use restriction enzymes to cut the DNA Load the DNA onto agarose gel for gel electrophoresis (next slide) Analyze the banding pattern

Unit 4, Topic 5 - Genetic Engineering

Unit 4, Topic 5 - Genetic Engineering Gel Electrophoresis Separates DNA fragments by size using electric current

Unit 4, Topic 5 - Genetic Engineering Gel Electrophoresis Larger fragments move more slowly Results in bands of DNA fragments of different lengths

Unit 4, Topic 5 - Genetic Engineering DNA Analysis Useful for: Forensic science (crime scene “fingerprints”) Determining paternity Looking at disease risk

Lab! We will be conducting a lab to determine whether or not a young woman carries one or two copies of a mutant gene This gene is called p53. The mutated version is linked to colon cancer. How do you think we will go about this? RFLPs and gel electrophoresis Besides the young woman’s, whose DNA should we also look at?

Unit 4, Topic 5 - Genetic Engineering Recombinant DNA DNA that is combined from two different organisms. One example: To insert genes of an organism into bacteria to harvest protein for medicine. Important players: Gene of interest (i.e. insulin, hGH, etc) Restriction enzymes Plasmid Bacteria

Making Recombinant DNA Unit 4, Topic 5 - Genetic Engineering Making Recombinant DNA Plasmids - self-replicating rings of DNA containing 2-30 genes, found in bacterial cells Plasmid and gene cut with same restriction enzymes Plasmid and gene have complementary “sticky” ends

Making Recombinant DNA Unit 4, Topic 5 - Genetic Engineering Making Recombinant DNA Cut the gene of interest using a restriction enzyme Cut the plasmid (using the same enzyme) Insert gene into the plasmid Insert the plasmid into bacteria Grow bacteria and harvest the protein

Unit 4, Topic 5 - Genetic Engineering How could you tell if the transformation really took place? The gene of interest is attached to a promoter and some kind of marker

Genetic Engineering Applications Unit 4, Topic 5 - Genetic Engineering Genetic Engineering Applications Pest-resistant crops (Bt toxin)

Genetic Engineering Applications Unit 4, Topic 5 - Genetic Engineering Genetic Engineering Applications Herbicide-resistant crops Fast-growing fish Green-glowing aquarium fish (jellyfish genes) Bacterial drug production (insulin, hGH)

Diagram on p. 14 in your packet (for #1-4)