1. Genetic technology Unit 4 Chapter 13

2. Selective Breeding • Choosing plants and animals with the most desired traits to be parents of the next generation • Increases amount of desired genes in a population • Inbreeding is mating between closely related individuals and ensures pure lines. • Overtime, inbreeding is detrimental because of deleterious recessive genes.

3. Selective breeding common in dogs and horses.

4. Hybrid vigor • A hybrid is the offspring of parents that have different forms of a trait. • Hybrids produced by crossing two purebred plants are often larger and stronger than their parents. • Plants are often hybrids.

5. Test cross • a method of breeding dominant phenotype individual to homozygous recessive individual to determine the dominant individual’s genotype • If the organism being tested is heterozygous, the expected 1:1 phenotypic ratio will be observed.

6. Genetic engineering • and more reliable method for increasing the frequency of a specific allele in a population • Recombinant DNA technology: cutting (cleaving) DNA from one organism into small fragments and inserting the fragments into a host organism of the same or a different species

7. Transgenic organisms • Plants and animals that contain functional recombinant DNA from an organism of a different genus are known as transgenic organisms because they contain foreign DNA.

8. Steps for recombining DNA • Isolate the foreign DNA fragment that will be inserted using restriction enzymes • bacterial proteins that have the ability to cut both strands of the DNA molecule at a specific nucleotide sequence called palindromes • Attach the DNA fragment to a carrier • Transfer into the host organism

9. Recombinant DNA technology

10. Restriction enzyme action Click on image to play video.

11. Vector • Mechanical or biological way for DNA from one species to be carried into a host cell Click on image to play video.

12. Gene cloning • After foreign DNA has been inserted into a plasmid, the recombined DNA is transferred into a bacterial cell. • Advantage: Bacteria reproduce quickly and can produce millions of copies of the recombinant DNA. • Each identical recombinant DNA molecule is called a gene clone.

13. Gene cloning using plasmid vectors

14. Cloned animal – Dolly the sheep

15. Polymerase chain reaction • Method to copy DNA outside of a living organism host • Heat, enzymes, and nucleotides are mixed in a machine to make multiple DNA copies.

16. Sequencing DNA • Machines in laboratories can determine the nucleotide order of small DNA fragments. • The DNA sequence can be visualized using gel electrophoresistechniques.

17. The entire human genome has been sequenced. • In 1990, scientists in the United States organized the Human Genome Project (HGP). It is an international effort to completely map and sequence the human genome, the approximately 35 000-40 000 genes on the 46 human chromosomes. • In February of 2001, the HGP published its working draft of the 3 billion base pairs of DNA in most human cells. • The sequence of chromosomes 21 and 22 was finished by May 2000.

18. Gel electrophoresis • DNA cut with restriction enzymes are loaded into a gel. • Electric currents separate the DNA fragments. • DNA from two sources can be compared for similarities.

19. Loading gel

20. Applying electric field to separate DNA

21. Comparing DNA fragments for similarities

22. DNA fingerprinting • DNA fingerprinting can be used to convict or acquit individuals of criminal offenses because every person is genetically unique

23. Recombinant DNA technology in society • Scientists have modified the bacterium E. coli to produce the expensive indigo dye that is used to color denim blue jeans. • Pharmaceutical companies already are producing molecules made by recombinant DNA to treat human diseases

24. Recombinant technology in society • Recombinant bacteria are used in the production of human growth hormone to treat pituitary dwarfism. • Also, the human gene for insulin is inserted into a bacterial plasmid by genetic engineering techniques. Recombinant bacteria produce large quantities of insulin • Scientists can study diseases and the role specific genes play in an organism by using transgenic animals • Crops have been developed that are better tasting, stay fresh longer, and are protected from disease and insect infestations

25. Gene therapy • Gene therapy is the insertion of normal genes into human cells to correct genetic disorders