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

2. 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

3. 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

4. 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

5. Unit 4, Topic 5 - Genetic Engineering

6. 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

7. 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

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

9. 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

10. Unit 4, Topic 5 - Genetic Engineering

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

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

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

14. 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?

15. 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

16. 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

18. 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

19. 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

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

21. 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)

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