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Biotechnology - History

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Biotechnology - History Selective Breeding * * * * * * * * * Selective Breeding The Wide Variety of Animals & Plants Used By Humans, Have Been Developed By Selective ... – PowerPoint PPT presentation

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Title: Biotechnology - History


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 Dont 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
Increasing Variation
  • Most Mutations Undesirable
  • Offspring Destroyed
  • Few Mutations Desirable
  • Breed To Maintain

11
Increasing VariationNew Kinds of Bacteria
  • Easy To Induce Mutations In Millions At Once
  • Mutations Particularly Useful
  • Produce Oil Eating Bacteria
  • Plastic Eating Bacteria

12
Increasing VariationNew 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 VariationNew 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
Allopolyploid
Polyploid formed between two closely related
species
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