13–1 Changing the Living World A. Selective Breeding 1. Hybridization 2. Inbreeding

1. Section Outline Section 13-1 • 13–1 Changing the Living World • A. Selective Breeding • 1. Hybridization • 2. Inbreeding • B. Increasing Variation • 1. Producing New Kinds of Bacteria • 2. Producing New Kinds of Plants Go to Section:

2. Selective Breeding • For centuries, humans have chosen desirable traits for dog breeding. This type of trait selection is called selective breeding. • There are two types of selective breeding: • Hybridization 2.Inbreeding

3. Hybridization • Luther Burbank (1849-1926) is deemed as one of the greatest selective breeders. He developed disease- resistant potatoes as well as many other varieties in plants. • Burbank often crossed different individuals to bring together the best of each organism. This is called hybridization. • Ex. Disease resistance x high food-producer

4. Inbreeding • *Risky business: Inbreeding causes individuals to be genetically similar, thus increasing the chances of bringing two recessive alleles together. ( Ex. Blindness in German Shepherds.) • After the desired qualities are established, many breeders then inbreed or continue to breed individuals together with similar characteristics.

5. Manipulating DNA • In the past, scientists had to rely on variation (natural and mutation generated) to produce changes in DNA. • Now, scientists can change DNA because: • Structure of DNA is known • Able to cut, extract and transfer pieces of DNA • Make unlimited copies of DNA

6. Genetic Engineering Making changes in the DNA code of a living organism. 3 Basic Steps: • DNA extraction • Cutting DNA • Separating DNA

7. DNA Extraction Taking DNA out of cells requires opening the cells and separating the DNA from the nucleus. (Hint: we did this procedure in class!)

8. Cutting DNA • DNA is cut into smaller fragments using restriction enzymes. • Hundreds of restriction enzymes are known. Each restriction enzyme cuts the DNA at a specific spot! (like a lock and key) Ex: EcoRI finds the sequence CTTAAG and cuts the DNA in that location. Ex:BamI -CCTAGG Ex: HaeIII CCGG

9. Restriction Enzymes Recognition sequences Section 13-2 DNA sequence Restriction enzyme EcoRI cuts the DNA into fragments. Sticky end Go to Section:

10. Separating DNA • After the DNA is cut, the fragments of DNA can be separated by size. • The smaller the DNA fragment the faster it moves! • Gel electrophoresis is used to separate DNA. *Used to compare genomes (Jerry Springer!) and identify specific genes.

11. Cell transformation the Big Picture! During transformation, a cell takes in DNA from outside the cell. (manipulated?) This external DNA becomes part of the cell’s DNA. Ex. Griffith’s pneumonia experiments.

12. Hybridization Inbreeding Dissimilar organisms Similar organisms Organism breed B Organism breed A Organism breed A Retains desired characteristics Combines desired characteristics Concept Map Section 13-1 Selective Breeding consists of which crosses which crosses for example for example which which Go to Section:

13. Figure 13-6 Gel Electrophoresis Section 13-2 Power source DNA plus restriction enzyme Longer fragments Shorter fragments Gel Mixture of DNA fragments Go to Section:

14. Transforming Cells and Cloning

15. Transforming Bacteria • External DNA fragment is cut using restriction enzymes. (ex. Growth gene). 2. External DNA is joined (sticky ends) to a small, circular piece of DNA called a plasmid. • Plasmid is inserted into a bacterial cell. • DNA replication occurs inside the bacterial cell. Making many copies of the external DNA.

16. Making Recombinant DNA Gene for human growth hormone Recombinant DNA Gene for human growth hormone Human Cell DNA recombination Sticky ends DNA insertion Bacterial Cell Bacterial chromosome Bacterial cell for containing gene for human growth hormone Plasmid Go to Section:

17. *Why use a plasmid? • Replication of the plasmid’s DNA can occur in bacteria • Contains a genetic marker (ex. Antibiotic resistance), making it easier to find the cell.

18. Transgenic Organisms • Transgenic organisms contain genes from other organisms. (ex: Firefly ‘glow’ gene inserted into tobacco plant) *Biotechnology- new industry resulting from genetic engineering.

19. Transgenic Microorganisms • Transgenic bacteria are used to produce many useful substances for health and industry. • Why bacteria? 1. Reproduce quickly 2. Easy to grow Examples: • Human proteins; cheap and abundant • Human insulin

20. Transgenic Animals • Used to study genes Ex. Mice with immune systems like humans-> study diseases • Improve the food supply Ex. Livestock with growth hormone-> faster growing and less fatty meat *Future animals that produce human proteins.

21. Transgenic Plants • Important part of food supply. Ex. Many contain genes that produce a natural insecticide. No need for synthetic pesticides. Ex. Rice with added vitamin A.

22. Cloning • A clone is a member of a population of genetically identical cells produced from a single cell. *1997- Dolly was cloned in Scotland by Ian Wilmut. In the news today: Cloned embryos okayed in Scotland.

24. Flowchart Section 13-4 Cloning A body cell is taken from a donor animal. An egg cell is taken from a donor animal. The nucleus is removed from the egg. The body cell and egg are fused by electric shock. The fused cell begins dividing, becoming an embryo. The embryo is implanted into the uterus of a foster mother. The embryo develops into a cloned animal. Go to Section:

25. Figure 13-13 Cloning of the First Mammal Section 13-4 A donor cell is taken from a sheep’s udder. Donor Nucleus These two cells are fused using an electric shock. Fused Cell Egg Cell The nucleus of the egg cell is removed. An egg cell is taken from an adult female sheep. The fused cell begins dividing normally. Embryo Cloned Lamb The embryo is placed in the uterus of a foster mother. The embryo develops normally into a lamb—Dolly Foster Mother Go to Section: