Genetic Engineering

1. Genetic Engineering

2. Selective breeding •  Selective breeding: • Inbreeding - Parents chosen for natural traits to be passed on to create new variations: increase food production, new pets, flowers • Hybridization—crossing dissimilar organisms to gain benefits from both (more food and pest resistant.

3. Inbreeding • Inbreeding: • Breeding within a small pool with the same traits to maintain the traits (dogs—dalmations, golden retrievers, etc.) • Increases chance of recessive traits being expressed (in dogs: blindness, hip problems, seizures, …)

4. Test Cross • Involves breeding an organism that has an unknown genotype with an organism that is homozygous recessive for the desired trait

5. Mutations • Some occur naturally, increase variation • Some human caused • Accidental—bacteria become resistant to antibiotics or vaccines. (MRSA) • Purposeful—use of mutagens (radiation, chemicals) to cause mutations

6. Genetic engineering • Technology that involves manipulating DNA from one organism in order to insert DNA from another organism (exogenous DNA)

8. DNA Tools • Genome – The total amount of DNA in the nucleus of each cell. • Restriction enzyme - recognize and bind specific DNA sequences and cleave the DNA within the sequence • ECO RI – specially cuts the sequence GAATTC.

9. Recombinant DNA technology • Newly generated DNA molecule containing DNA from another source. • Carrier or vector (plasmids or viruses) transfers the recombinant DNA into the bacterial cell • Plasmid – small, circular double stranded DNA found in bacteria or yeast cells. • DNA ligase will glue ends of the DNA fragments.

12. Gel Electrophoresis • Electric current is used to separate the DNA fragment according to the size of the fragment. • DNA is loaded into the negatively charged end. • Electric current is applied. • Fragments move towards the positive end. • The smaller fragments move towards the positive end faster than the larger fragments. • The unique patterns created are based on the size of the DNA fragment can be compared to known DNA fragment patterns. • Portions of the fragment bands can be removed for study.

13. Gel Electrophoresis

14. Clones • From a single cell; identical to the parent cell • First cloned mammal—sheep, Dolly • Now cows, pigs, mice, …

15. Cloning process to form Dolly • Donor cell taken from adult udder • An egg cell is donated; nucleus is removed • The two cells are fused by electric shock • Fused cell begins dividing into an embryo • The embryo placed into uterus of a third sheep • The embryo grows into an organism as a normal fetus does and goes through the birth process

16. Cloning in humans? • Being studied • Many ethical questions

17. Transformation (remember Griffith)

18. DNA Manipulation • Chromosome or plasmid (small circular DNA) • DNA is removed from a cell (bacteria, etc). • DNA is cut by enzymes at specific sites. • A section of DNA from another organism is attached. (Human, plant, animal,…). • DNA is returned to the cell • Called recombinant DNA • Human insulin produced from bacteria this way.

20. PCR (polymerase chain reaction) • method of making many copies of a small amount of DNA for study or testing

21. Transgenic Organisms • Contain genes from a different species • Bacteria • can produce human insulin, human growth hormone and human clotting factor. • Animals • Research—mice transformed to have immune system like human’s to study effects of disease on it • Larger livestock—extra copies of growth hormone genes

22. Plants • Large part of food plants are transgenic (genetically modified) • Soybeans (52%), corn (25%) • Genes for natural insecticide, ability to survive weed-killing chemicals, produce more per acre.

23. New Bacteria and Plants • Bacteria that digest oil • Polyploidy in plants (fatal in animals) creates new varieties often larger and stronger than parents. (crop plants—more food per acre)

24. DNA Fingerprinting • blood, sperm, and other body tissues can be tested • Analyses sections of DNA with little function which are different in different people • Used since late 1980’s • DNA is cut with many restriction enzymes into many small pieces • DNA is placed in a gel and electricity is applied • Electricity causes pieces to migrate. Smaller pieces travel farther. Pattern formed and can be compared to other DNA.

25. The Human Genome Project • Collaborative effort to map genes in human DNA • Completed in 2003 • Now information is being used by scientists

26. Bioinformatics • Bioinformatics – Involves creating and maintaining databases of biological information • Scientists will be able to study the evolution of genes by grouping proteins sequences of families of related sequence and comparing different organisms.

27. Genomics - study of the genomes of organisms (sequencing, mapping, & gene interactions)Proteomics - study of the entire complement of proteins in a system or organismPharmacogenomics- study of how genetics inheritance affects the body’s response to drugs.

28. DNA Microarrays • Tiny microscope slides or silicon chip containing DNA fragment. • Can store large amounts of genetic information • Can contain genes that control the cell cycle or the entire human genome http://www.bio.davidson.edu/Courses/genomics/chip/chip.html

29. The Hapmap Project • A group of scientist creating a catolog of common genetic variation that occur in humans.

30. Gene Therapy • A technique aimed at correcting mutated genes that cause human diseases.