Genetic Engineering

1. Genetic Engineering

2. Genetic Engineering • Process of making changes in the DNA code of living organisms • What kinds of organisms have humans genetically engineered? • How have humans been able to genetically engineer these types of animals? • The answer lies in Selective Breeding

3. Selective Breeding • Selective breeding takes advantage of naturally occurring genetic variation in plants, animals, and other organisms, to pass desired traits on to the next generation of offspring • Luther Burbank – created disease – resistant potato to help the Irish potato famine • Burbank used Hybridization • Crossing dissimilar individuals to bring together the best of both organisms

4. Selective Breeding

5. Selective Breeding • Inbreeding • The continued breeding of individuals with similar characteristics • Helps to insure the characteristics that makes each breed unique will be preserved • However, can lead to genetic defects due to two recessive alleles since they are genetically similar

6. Manipulating DNA

7. Manipulating DNA • Different techniques are used – • To extract DNA from cells • To cut DNA into smaller pieces • To identify the sequence of bases in a DNA molecule • To make unlimited copies of DNA • Gel Electrophoresis and Polymerase Chain Reaction (PCR) are two of these such techniques

8. Gel Electrophoresis • Restriction enzymes are used to cut DNA molecules into smaller fragments • A restriction enzyme will cut a DNA sequence only if it matches the sequence precisely • These fragments are placed in a porous gel and voltage is applied to the gel • DNA fragments move from towards the positive end since DNA is negatively charged • The smaller the fragment, the farther it will travel down the gel

9. Gel Electrophoresis

10. Recombinant DNA • Synthetic DNA sequences can be joined to natural ones using enzymes that splice DNA together • Also, a gene from one organism can be removed and attached to DNA of another organism

11. Polymerase Chain Reaction • Scientists uses this method to produce many copies of a gene

12. Cell Transformation

13. Transformation • A cell takes in DNA from outside the cell and then becomes a component of the cell’s DNA • Often used with bacteria (i.e. Griffith’s experiment)

14. Importance of Plasmids • Two essential features – • Plasmid DNA has a DNA sequence that helps promote plasmid replication • Plasmid also has a genetic marker – a gene that makes it possible to distinguish bacteria that carry the plasmid and those that don’t

15. Genes for antibiotic resistance are often used in bacteria to transform bacterial DNA

16. Biotechnology

17. Transgenic Organisms • Transgenic – contain genes from other species (Genetically Modified Organisms (GMOs)) • Types – • Bacteria – used to produce insulin, growth hormone, and clotting factor cheaply • Animals – mice used in research, livestock producing leaner meat • Plants – soybeans and corn grown as GMO that produce natural insecticides

18. Cloning • A clone is a member of a population of genetically identical cells produced from a single cell • Famous clone – Dolly the sheep • What would be some benefits of cloning? • Some drawbacks to cloning?

20. Dolly Dolly is the adult sheep, whereas the young, white sheep is Dolly’s first offspring

21. Human Genetics

22. Human Genome • The human genome, our complete set of genetic information, includes tens of thousands of genes • Identification of genes in the human genome has helped to diagnose many genetic disorders

23. Genetic Disorders Recessive Disorders Dominant Disorders • PKU (Phenylketonuria) – lack the enzyme to break down phenylalinine • Tay-Sachs – nervous system breakdown • Achondroplasia – dwarfism • Huntington Disease – progressive loss in muscle control and mental function

24. How Changes Affect an Individual Cystic Fibrosis and Sickle Cell Disease

25. Cystic Fibrosis • Caused by a deletion of 3 bases in a protein that causes the protein to be destroyed • Cannot properly transport Cl- in membrane of cells

26. Cystic Fibrosis

27. Sickle Cell Disease • Red blood cells have a twisted and bent shape • RBC get stuck in capillaries causing damage to cells, tissues, and organs • Produces physical weaknesses and damage to the brain, heart, and spleen • Caused by a change in hemoglobin protein – Glu Acid  Val

28. Sickle Cell Disease

29. Chromosomal Disorders • Due to nondisjunction – when homologous chromosomes fail to separate • Abnormal number of chromosomes may find their way into gametes, where a disorder of chromosome number will occur

30. Sex Chromosome Disorders • Turner Syndrome – a female inherits only one X • Unable to reproduce • Klinefelter’s Syndrome – a male inherits an extra (or numerous copies) of the X chromosome • Unable to reproduce

31. Gene Therapy

32. Gene Therapy • Information from the Human Genome Project may be used to cure genetic disorders • Through gene therapy, the process of changing the gene that causes a genetic disorder, scientists may eliminate the cause of the disorder • Allowing the body to make the correct protein or enzyme

33. Gene Therapy Process • Viruses are used because of their ability to enter a cell’s DNA • Viruses are modified so they cannot cause disease • DNA fragment containing a replacement gene is spliced in • Patient is then infect with the virus, which should carry the gene into the cells and correct the genetic defects

34. Ethical Issues • What will happen to the human species if we gain the opportunity to design our bodies? • What will be the consequences if we clone humans from identical copies of their cells? • If we cure disease, should we engineer taller people or alter eye color, hair texture, sex, blood group, or appearance?