1. Biotechnology - History
Selective Breeding

2. Selective Breeding
The Wide Variety of Animals & Plants Used By Humans, Have Been Developed By Selective Breeding – Allowing Only Those Animals & Plants With Desired Characteristics Are Allowed To Reproduce.

3. Selective Breeding
Key Concept:
Humans Use Selective Breeding To Pass Desired Traits On To The Next Generation of Organisms
Apples, Corn, Potatoes
Dogs, Cattle, Mice, Yeast

4. Selective Breeding Luther Burbank 1849-1926 800 Varieties of Plants
Disease Resistant Potatoes

5. Selective Breeding - Hybridization
Crossing Dissimilar Individuals To Bring Together The Best Of Both Organisms
Often Hardier Than Parents
Disease Resistance + Increased Food Producing Capacity

6. Selective Breeding - Hybridization
Postzygotic Barriers
Reduced Hybrid Viability
Embryos Don’t Develop
Reduced Hybrid Fertility
Offspring Vigorous but Sterile
Hybrid Breakdown
1st Generation Viable & Fertile
2nd Generation Feeble & Sterile

7. Selective Breeding - Inbreeding
Used To Maintain A Desired Characteristic
Dog Breeds
Higher Risk of Homozygous Recessive Alleles for Genetic Defect.
Blindness & Joint Problems In German Shepherds & Golden Retrievers

8. Increasing Variation
Key Concept:
Breeders Can Increase The Genetic Variation In A Population By Inducing Mutations

9. Increasing Variation
Selective Breeding Impossible Without A Diverse Gene Pool
Importance Of Diversity In Wild Populations
Mutations Induced Through
Radiation
Chemicals

10. Most Mutations Undesirable Few Mutations Desirable
Increasing Variation
Most Mutations Undesirable
Offspring Destroyed
Few Mutations Desirable
Breed To Maintain

11. Increasing Variation New Kinds of Bacteria
Easy To Induce Mutations In Millions At Once
Mutations Particularly Useful
Produce Oil Eating Bacteria
Plastic Eating Bacteria

12. Increasing Variation New Kinds of Plants
Drugs Disrupt Chromosomal Separation During Meiosis
Polyploidy
Offspring 2X or 3X Chromosomes
Usually Fatal For Animals
Tolerated & Useful In Plants

13. Increasing Variation New Kinds of Plants
Polyploidy
May Instantly Produce A New Species Larger & Stronger Than Their Diploid Relatives
Bananas, Strawberries, Oats, Cotton, Tobacco, Wheat

14. Increasing Variation – New Kinds of Plants
Allopolyploid
Two Different Species From the Same Genus To Form A Polyploid Hybrid
Bread Wheat – Triticum aestivum
8000 years ago
Cultivated Wheat & Wild Grass

15. Polyploid formed between two closely related species
Allopolyploid
Polyploid formed between two closely related species