1. Biotechnology Chapter 10

2. Golden Rice  Rice plants with added genes make and store beta carotene

3. Video: Golden rice or Frankenfood?

4. GMOs and Transgenic Organisms  Transgenic An organism that has been genetically modified with genes from a different species  Genetically modified organisms (GMOs) Organism whose genome has been modified by genetic engineering

5. 10.2 Finding Needles in Haystacks  Gene research was limited until enzymes produced by bacteria to cut viral DNA were discovered  Restriction enzyme Enzyme that cuts DNA at specific base sequences Used in DNA cloning to cut DNA into pieces that are inserted into cloning vectors

6. DNA Cloning  DNA cloning mass-produces DNA fragments for research  DNA cloning Set of procedures that uses living cells to make many identical copies of a DNA fragment  Clone A genetically identical copy of DNA, a cell, or an organism

7. Cloning Vectors  Cloning vector A DNA molecule that can accept foreign DNA, resulting in a hybrid molecule that can be transferred to a host cell, and get replicated in it  Plasmid A small, circular DNA molecule in bacteria, replicated independently of the chromosomes A cloning vector

8. Recombinant DNA  Recombinant DNA molecules are introduced into host cells such as bacteria, which copy the DNA as they divide  Recombinant DNA Contains genetic material from more than one organism

9. Making Recombinant DNA 1. A restriction enzyme recognizes specific base sequences in DNA from two different sources 2. Restriction enzymes cut DNA into fragments with single-stranded tails (“sticky ends”) 3. DNA fragments from different sources are mixed together; matching sticky ends base-pair 4. DNA ligase joins fragments, forming recombinant DNA

10. Fig. 10-2, p. 181 restriction enzyme (cut) DNA ligase (paste) 1 A restriction enzyme recognizes a specific base sequence in DNA (green boxes) from two sources. 2 The enzyme cuts DNA from both sources into fragments that have sticky ends. 3 The DNA fragments from the two sources are mixed together. The matching sticky ends base-pair with each other. 4 DNA ligase joins the fragments of DNA where they overlap. Molecules of recombinant DNA are the result. mix Making Recombinant DNA

12. Fig. 10-3, p. 181 Bam Hl Pst l Sph l Kpn l Eco RI Sal l Acc l Xho l Xba l Sac l Bst XI Not l Cloning Vector 3.85 kb Plasmid

13. The use of mRNA for the Identification of DNA mRNA sequence comes from specific regions of DNA (Genes) mRNA sequence is used to make proteins and defines the physical/behavioral characteristics of the organism Therefore we use mRNA to identify active regions of DNA Use mRNA sequence and base pairing rules to identify DNA original sequence

14. cDNA Cloning  RNA cannot be cloned directly; reverse transcriptase is used to copy single-stranded RNA into cDNA for cloning  Reverse transcriptase Viral enzyme that uses mRNA as a template to make a strand of DNA  cDNA DNA synthesized from an RNA template by the enzyme reverse transcriptase

15. Making cDNA

16. Fig. 10-4, p. 182 mRNA A The enzyme reverse transcriptase transcribes mRNA into DNA. mRNA cDNA B DNA polymerase replicates the DNA strand. cDNA Eco RI recognition site C The result is a double-stranded molecule of DNA that can be cut and pasted into a cloning vector. Stepped Art

17. Libraries  A library is a collection of cells that host different fragments of DNA, often representing an organism’s entire genome  Researchers make DNA libraries to isolate one gene from the many other genes in a genome  Genome An organism’s complete set of genetic material

18. Nucleic Acid Hybridization  Probes are used to identify one clone that hosts a DNA fragment of interest among many other clones in a DNA library  Probe Short fragment of DNA labeled with a tracer Hybridizes with a specific nucleotide sequence  Nucleic acid hybridization Base-pairing between DNA or RNA from different sources

19. PCR  PCR quickly mass-produces copies of a particular DNA fragment for study  Polymerase chain reaction (PCR) Uses primers and heat-resistant DNA polymerase to rapidly generate many copies of a DNA fragment  Primer Short, single-strand of DNA designed to hybridize with a DNA fragment

20. Steps in PCR 1. Starting material is mixed with DNA polymerase, nucleotides and primers 2. Mixture is heated and cooled in cycles At high temperature, DNA unwinds At low temperature, primers base-pair with template DNA 3. Taq polymerase synthesizes complementary DNA strands on templates

21. 2 When the mixture is heated, the double-stranded DNA separates into single strands. When it is cooled, some of the primers base-pair with the template DNA. 4 The mixture is heated again, and the double-stranded DNA separates into single strands. When it is cooled, some of the primers base-pair with the template DNA. Fig. 10-5, p. 183 1 DNA template (blue) is mixed with primers (red), nucleotides, and heat- tolerant Taq DNA polymerase. Stepped Art 3 Taq polymerase begins DNA synthesis at the primers, and complementary strands of DNA form on the single-stranded templates. 2 When the mixture is heated, the double-stranded DNA separates into single strands. When it is cooled, some of the primers base-pair with the template DNA. 5 Taq polymerase begins DNA synthesis at the primers, and complementary strands of DNA form on the single-stranded templates. 4 The mixture is heated again, and the double-stranded DNA separates into single strands. When it is cooled, some of the primers base-pair with the template DNA. Two Rounds of PCR

22. Animation: Polymerase chain reaction (PCR)

23. Animation: Formation of recombinant DNA

24. Animation: Use of a radioactive probe

25. Animation: Base-pairing of DNA fragments

26. Animation: How to make cDNA

27. Animation: Restriction enzymes

28. Animation: F2 ratios interaction

29. 10.3 Studying DNA  Short tandem repeats are multiple copies of a short DNA sequence that follow one another along a chromosome  The number and distribution of short tandem repeats, unique in each individual, is revealed by electrophoresis as a DNA fingerprint

30. DNA Fingerprinting  DNA fingerprinting is used in forensics, court evidence, and other applications  DNA fingerprint An individual’s unique array of short tandem repeats  Electrophoresis Used to separate DNA fragments by size

31. Fig. 10-6, p. 184 Evidence from Crime Scene Size ReferenceControl DNASize ReferenceVictimSuspect 1Suspect 2 Female Cells SemenSize ReferenceBoyfriendControl DNA Size Reference DNA Fingerprinting: A Forensic Case

32. The Human Genome Project  Automated DNA sequencing and PCR enabled scientists to sequence the more than 3 billion bases of the human genome  Sequencing Method of determining the order of nucleotides in DNA

33. Sequencing a Fragment of DNA  The order of colors is the order of DNA bases (A, T, G, C)

34. Genomics  Analysis of the human genome sequence is yielding new information about human genes and how they work  Genomics The study of genomes (structural genomics, comparative genomics)

35. Some Sequenced Genomes

36. Animation: Automated DNA sequencing

37. Animation: DNA fingerprinting

38. Video: ABC News: DNA mystery: Human chimeras

39. Video: ABC News: Family ties: Paternity testing

40. 3D Animation: Gene sequencing

41. 10.4 Genetic Engineering  Recombinant DNA technology and genome analysis are the basis of genetic engineering  Genetic engineering is the directed alteration of an individual’s genome, resulting in a genetically modified organism (GMO)  Genetic engineering Process by which deliberate changes are introduced into an individual’s genome

42. Genetically Modified Microorganisms  A transgenic organism carries a gene from a different species  Transgenic organisms are used in research, medicine, and industry  Transgenic bacteria and yeast produce medically valuable proteins

43. Designer Plants  Transgenic crop plants help farmers produce food more efficiently  Plants with modified or foreign genes are now common in farm crops

44. Fig. 10-8, p. 187 1 An A. tumefaciens bacterium has been engineered to contain a Ti plasmid. The plasmid carries a foreign gene. 2 The bacterium infects a plant cell and transfers the Ti plasmid into it. The plasmid DNA becomes integrated into one of the cell’s chromosomes. 3 The plant cell divides, and its descendants form an embryo. 4The embryo develops into a transgenic plant. 5 The transgenic plant expresses the foreign gene. This tobacco plant is expressing a gene from a firefly. Using the Ti plasmid to Make a Transgenic Plant

45. Animation: Gene transfer using a Ti plasmid

46. Genetically Modified Crops  Bt gene confers insect resistance to corn

47. Biotech Barnyards  Transgenic animals produce human proteins  Animals that would be impossible to produce by traditional breeding methods are being created by genetic engineering  Transgenic animals are used in research, medicine, and industry

48. Transgenic Animals

49. Knockout Cells and Organ Factories  Transgenic animals may one day provide a source of organs and tissues for transplantation into humans  Xenotransplantation Transplant of an organ from one species to another

50. Animation: Transferring genes into plants

51. Video: ABC News: Cloned pooch

52. Video: ABC News: Mule clones

53. Video: ABC News: Glow-in-the-dark pigs

54. Video: ABC News: Cloned food approved

55. 10.5 Genetically Modified Humans  Genes can be transferred into a person’s cells to correct a genetic defect or treat a disease  However, the outcome of altering a person’s genome remains unpredictable  Gene therapy Transfer of a normal or modified gene into an individual with the goal of treating a genetic defect or disorder

56. Unpredictable Outcomes  There are more than 15,000 serious genetic disorders – gene therapy is the only real cure  In some cases, gene therapy works – in other cases it leads to death Inserting a virus-injected gene into a chromosome can disrupt normal function and cause cancer Severe allergic reaction to the viral vector can cause death

57. One Successful Case of Gene Therapy  Rhys Evans, born with a severe immune disorder (SCID-X1) received a normal gene and no longer lives in isolation

58. Getting Perfect  Eugenics Idea of deliberately improving the genetic qualities of the human race  The potential benefits of genetically modifying humans must be weighed against the potential risks, including social implications

59. 10.6 Impacts/Issues Revisited  Golden rice with beta carotene was ready for distribution in 2005 but is still not available for human consumption – the biosafety experiments required are too expensive for the public humanitarian agency that developed it

60. Digging Into Data: Enhanced Spatial Learning in Mice With Autism Mutation