1. Ch 15 DNA Technology/ Genetic Engineering

2. Selective Breeding
Selective Breeding – humans take advantage of naturally occurring genetic variation to pass wanted traits on to the next generation of organisms.
2 methods:
Hybridization – crossing dissimilar individuals to bring together the best of both organisms.
Inbreeding – the continued breeding of individuals with similar characteristics.

3. Increasing Variation
Breeders can increase the genetic variation in a population by introducing mutations, which are the ultimate source of biological diversity.
Biotechnology – the application of a technological process, invention, or method to living organisms.

4. DNA Extraction Chemical treatments cause cells and nuclei to burst
The DNA is inherently sticky, and can be pulled out of the mixture
This is called “spooling” DNA

5. “Spooled” DNA

6. Cutting DNA Restriction enzymes cut DNA at specific sequences
Useful to divide DNA into manageable smaller fragments

7. Electrophoresis Also known as DNA fingerprinting.
Used in forensics – study of crime scene evidence.
DNA can be separated based on size and charge
The phosphate groups are negatively charged
DNA is placed in a gel and electricity is run through

8. Electrophoresis Negative DNA moves toward the positive end of the gel
Smaller fragments move farther and faster through the gel.

9. Electrophoresis

10. Steps in DNA Sequencing
Many copies of a single strand of DNA are placed in a test tube
DNA polymerase is added
A mixture of DNA nucleotides is added some of which have dye molecules attached
Each base (A,T,C,G) has a different color dye

11. Steps in DNA Sequencing
The enzyme uses the unknown strand of DNA to make a new strand.
By chance, some dyed nucleotides & some regular ones are added
Dye molecules are large and stop the chain from growing

12. DNA Sequencing
The result is DNA fragments of multiple sizes with colors that can be identified

13. DNA Sequencing
After the gel separates the resulting fragments by size, we 'read' the sequence from bottom to top.

14. Copying DNA Polymerase Chain Reaction Also called PCR
A method of making many copies of a piece of DNA or gene.

15. Steps in Copying DNA A DNA molecule is placed in a small test tube
DNA polymerase that can work at high temps is added

16. Steps in Copying DNA The DNA is heated to separate the two strands
Primers, short pieces of DNA, complementary to the ends of the molecule to be copied, are added
Provide the place for the DNA polymerase to start working

17. Copying DNA
The tube is cooled, and DNA polymerase adds new bases to the separated strands

18. Large amounts of DNA can be made from a small starting sample
PCR
Large amounts of DNA can be made from a small starting sample

19. Cloning
Clone- a member of a group of genetically identical cells produced from a single cell.
A body cell from one organism and an egg cell from another are fused
The resulting cell divides like a normal embryo

20. Cloning “Dolly” 1997

21. Human Genome Project Started in 1990
Research effort to sequence all of our DNA (46 chromosomes)
Over 3.3 billion nucleotides
Mapping every gene location (loci)
Conducted by scientists around the world

22. Benefits of Human Genome Project
Improvements in medical prevention of disease, gene therapies, diagnosis techniques …
Production of useful protein products for use in medicine, agriculture, bioremediation and pharmaceutical industries.
Improved bioinformatics – using computers to help in DNA sequencing …

23. Recombinant DNA
Recombinant DNA – joining together DNA from two or more sources.
This technique makes it possible to change the genetic composition of living organisms.

24. Biotechnology and Benefits of Genetic Engineering:
The use of gene science to create new products from plants and animals
Improved food products
Medical advances
An enhanced environment

25. Biotechnology Breakthroughs
Insulin (1982)
First commercial biotech product
Reliable, inexpensive source of insulin
Rice
Enriched with beta-carotene and iron
Bananas
Containing edible hepatitis vaccine

26. Biotechnology Breakthroughs
Potatoes with higher solid content
Garlic that lowers cholesterol
Fruits and vegetables that reduce risks of cancer and heart disease

27. Environmental Benefits
Reduced pesticide use
Lower energy requirements
Cleaner water
Less soil erosion