1. Concepts and Applications Seventh Edition
Powerpoint Lecture Outline
Human Genetics
Concepts and Applications
Seventh Edition
Ricki Lewis
Prepared by
Mary King Kananen
Penn State Altoona

2. Chapter 19 Genetically Modified Organisms

3. Transgenic Animals
Have genetic modifications and carry that genetic alteration from other organisms in all of their cells
Example
Genetically modified pigs were engineered to produce less polluting manure
Chapter Opener 19

4. Biotechnology
Use or alteration of cells or biological molecules for specific application
Transgenic organisms are possible, but the genetic code is universal
Ethical and legal issues to be considered including patent laws
Figure 19.1

5. Technology Timeline

6. Amplifying DNA Polymerase chain reaction (PCR)
Molecular
Increases the amount of a DNA sequence
Replicates sequence millions of times
Recombinant DNA technology
Amplifies DNA that includes
Within cells
Sequences from other organisms

7. Uses of PCR
Table 19.1

8. Figure 19.2

9. Transcription-Mediated Amplification
Copies target DNA into RNA and then uses RNA polymerase to amplify RNA
Does not require temperature shifts
Makes 10 billion copies in ½ hour
Used to develop a test for HIV, sensitive enough to detect early infections

10. Recombinant DNA
Recombinant DNA is a molecule that combines DNA from two sources
Also known as gene cloning
Creates a new combination of genetic material
Human gene for insulin was placed in bacteria
The bacteria are recombinant organisms and produce insulin in large quantities for diabetics
Genetically modified organisms are possible because of the universal nature of the genetic code

11. Creating Recombinant DNA Molecules
Cut DNA from donor and recipient with the same restriction enzymes
Cut DNA fragment is combined with a vector
Vector DNA moves and copies DNA fragment of interest
Vector cut with restriction enzymes
The complementary ends of the DNAs bind and ligase enzyme reattaches the sugar-phosphate backbone of the DNA

12. Creating Recombinant DNA Molecules
Figure 19.3a

13. Figure 19.3b

14. Figure 19.3c

15. Vectors
Are DNA molecules that can be moved into and replicated in an organism
They are classified by
The organisms that replicated the vector
The size of DNA that can be inserted
Table 19.2

16. Plasmids
Figure 19.4

17. Recombinant DNA
Figure 19.5

18. Isolating Gene of Interest
Genomic library
Collections of recombinant DNA that contain pieces of the genome
DNA probe
Radioactively labeled gene fragments
cDNA library
Genomic library of protein encoding genes produced by extracting mRNA

19. Figure 19.6

20. Selecting Recombinant Molecules
Three types of cells can result from attempt to introduce a DNA molecule into a bacterial cell:
Cells lack plasmid
Cells contain plasmid that do not contain foreign genes
Cells that contain plasmids with foreign genes

21. Selecting for Cells with Vectors
Vectors are commonly engineered to carry antibiotic resistance genes
Host bacteria die in the presence of the antibiotic
Bacteria harboring the vector survive
Growing cells on media with antibiotics ensures that all growing cells must carry the vector

22. Figure 19.7

23. Figure 19.8

24. Selecting Cells with Inserted DNA
The site of insertion of the DNA of interest can be within a gene on the vector
Insertion of a DNA fragment will disrupt the vector gene
The gene lacZ produces an enzyme and bacteria to turn blue in the presence of certain media
Insertions in the lacZ gene prevent lacZ enzyme production and the bacteria are white
Bacteria with vectors that are white carry an DNA inserted in the lacZ gene
Rare mutations in the lacZ gene will also make white bacteria

25. Applications of Recombinant DNA
Recombinant DNA is used to:
Study the biochemical properties or genetic pathways of that protein
Mass produce a particular protein (e.g., insulin)
Sometimes conventional methods are still the better choice
Textile industry can produce the dye indigo in E. coli by genetically modifying genes of the glucose pathway and introducing genes from another bacterial species

26. Table 19.3

27. The Dye Indigo The blue in blue jeans
Originally came from mollusks or fermented leaves of woad or indigo plants
Synthetic process uses coal tar; releases toxic by-products
With recombinant DNA E. coli can produce indigo

28. Transgenic Organisms
When recombinant DNA is applied to multicellular organisms, individuals must be bred to yield homozygous individuals
Plants may be produced by asexual reproduction (cuttings)
Different vectors and gene transfer techniques can be used

29. Making a Transgenic Plant
Figure 19.9
May use Ti plasmids to obtain foreign DNA

30. Bt Insecticide gene From bacterium
Bacillus thuringiensis (bt)
Specifies a protein that destroys the stomach lining of certain insect larva
2/3 of U.S. corn is transgenic for the bt gene

31. Table 19.4

32. Table 19.5

33. Transgenic Animals More difficult than plants
Several techniques to insert DNA
Chemicals to open holes in plasma membrane and liposomes carry DNA in cells
Electroporation–a brief jolt of electricity to open membrane
Microinjection–uses microscopic needles
Particle bombardment – a gun like device shoots metal particles coated with foreign DNA

34. Figure 19.10

35. Bioremediation
Transgenic organisms can provide process as well as products
Ability to detoxify pollutants
Examples
Hg-contaminated soils
GFP gene reveal locations of land mines

36. Gene Targeting
A more precise method for modifying genes of an organism
Homologous recombination is a natural process in which DNA sequences, which are similar or identical, recombine (mechanism of crossing over)
Introduction of homologous DNA flanking an insertion in a vector allows homologous recombination to occur

37. Gene Targeting
Figure 19.11

38. Knockout Mutations in Mice
May create a model system for studying human disease
Identify animal version of a human disease causing allele
Transfer the corresponding human mutant allele to mouse ES cells
Breed homozygous individuals
Use mice to investigate disease symptoms and treatments

39. Examples of Knockout Mouse Models
Severe combined immune deficiency due to ADA gene deficiency
Sickle cell disease
Polygenic disorders e.g., atherosclerosis by inactivating combinations of lipid metabolism genes
Prenatal aspects of neurofibromatosis type I

40. Normal Knockouts
Some genes can be knocked out and have no apparent effect on phenotype
Other genes encode the same or similar proteins that can compensate (redundancy)
Absent protein does not cause an effect but an abnormal protein might
Gene may have no function or different role than hypothesized
Conditions required to observe phenotype were not present
Example: X collagen in skeletal repair

41. Monitoring Gene Function
Gene Expression Profiling
Indicates genes transcribed
DNA Variation Screening
Detects mutations in Single Gene Polymorphisms (SNPs)
Microarray Comparative Genomic Hybridization
Deletions and amplifications of DNA sequences between cells or species

42. Figure 19.12

43. Figure 19.12

44. Figure 19.12

45. Table 19.6

46. Figure 19.13

47. Solving a Problem
Figure 19.14