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Ch 15 DNA Technology/ Genetic Engineering

Ch 15 DNA Technology/ Genetic Engineering. 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:

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Ch 15 DNA Technology/ Genetic Engineering

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  1. Ch 15DNA 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 enzymescut 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 DNAmoves toward the positive end of the gel • Smaller fragments move farther andfaster 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 polymeraseis 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. 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 cellfrom 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 proteinproducts for use in medicine, agriculture, bioremediation and pharmaceutical industries. • Improvedbioinformatics– 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

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