Chapter 20 DNA Technology & Genomics

Transcription

1 Chapter 20 DNA Technology & Genomics

2 Focus of Chapter An introduction to the methods and developments in: Recombinant DNA Genetic Engineering Biotechnology

3 Recombinant DNA DNA in which genes from different sources are linked. Ex: the green mice

4 Genetic Engineering The direct manipulation of genes for practical purposes. Ex: Using E. coli to produce human insulin.

5 Biotechnology The use of living organisms or their components to perform practical tasks. Ex: the use of bacteria to digest oil spills.

6 Restriction Enzymes Cut DNA at specific nucleotide sequences called restriction sites. Used to "cut and splice" DNA. Obtained from bacteria. Ex. EcoRI and Hind III

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8 Plasmids Used extensively in Biotechnology and Recombinant DNA. Serve as a vehicle for transporting genes. Comment other vehicles are used in other methods

9 Steps for Plasmid Use 1. Get the DNA for the trait. 2. Insert DNA into the plasmid. 3. Bacterial Transformation. 4. Identification of the new trait.

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11 Insertion Placing foreign DNA into a plasmid. Open plasmid with restriction enzymes to create sticky ends. Splice the new DNA and plasmid together.

12 Transformation Placing the plasmid into a bacterial cell. Reminder - our lab need to know for AP testing purposes.

13 Transformation Methods Temperature shock & salt treatment Electric current Injection

14 Identification Screening the altered cells for the desired gene. Ex: Antibiotic sensitivity or the expression of a new trait (color, glowing etc.).

15 Example Applications 1. Insulin 2. Human Growth Hormone 3. Other Proteins

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17 Comment Gene can t be above a certain size (12 kb) or a plasmid won t work. mrna must not need splicing to remove introns. Why?

18 DNA Sources 1. Organism - use a section of their chromosome. 2. cdna - Complementary DNA - created copy of DNA from the mrna transcript to avoid introns. Uses reverse transcriptase.

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20 Other Vehicles BACs Bacteria Artificial Chromosome handle inserts of kb YACs Yeast Artificial Chromosome have a centromere and telomomere, handle inserts >300 kb HACs Human Artificial Chromosome

21 Nucleic Acid Probes Used to find a specific DNA sequence in a mixture of DNA pieces

22 How Used DNA is denatured and cut to produce single stranded pieces. Piece of compliment DNA is added as a probe. The probe has been labeled. Look for where the probe goes in the DNA sample.

23 Probe DiagramNuNu

24 DNA Microarray

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26 PCR Polymerase Chain Reaction Method for making many copies of a specific segment of DNA. Also called DNA Amplification.

27 PCR - Method 1. Separate strands by heating (denature the DNA). 2. Cool slightly. 3. Build new strand from primers and nucleotides. 4. Repeat.

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29 Importance - PCR Can amplify any DNA with as little as one original copy. Very useful in a variety of techniques and tests.

30 Gel Electrophoresis Technique will be covered in lab. Used to separate mixtures of DNA or proteins.

31 RFLP Analysis Restriction Fragment Length Polymophisms. Method for detecting minor differences in DNA sequence between individuals. Common in DNA fingerprinting

32 Method 1. Digest DNA with restriction enzymes. 2. Separate pieces by Gel Electrophoresis 3. Identify sequences with probes.

33 RFLP - Results Patterns of DNA markers or DNA fingerprint Markers are inherited in a Mendelian pattern and can show relationships (Pedigree studies).

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36 DNA Sequencing Old Method Uses dideoxynucleotides which stop DNA Polymerase at a known point in DNA replication. Builds new DNA from single strand DNA. Produces fragments of different lengths.

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38 DNA Sequencers

39 Application DNA sequence is read base by base. By sequencing overlapping pieces of chromosomes, the entire genome of an organism can be read. (chromosome walking)

40 Cloning of Organisms Reproducing an organisms by asexual means. Commonly done in plants. Shows the concept of Totipotency that a single cell can develop into a new organism.

41 Cloning in Plants

42 Cloning in Animals Has been done by nuclear transplantation. Examples Dolly Many other vertebrates have now been cloned.

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44 Dolly Picture

45 Stem Cells Stem Cell an unspecialized cell that can reproduce itself or differentiate into other cells.

46 Types of Stem Cells Embryonic from an embryo. Adult found in various tissues of the adult body.

47 Research Attempting to use stem cells to replace damaged cells or body parts. If can use own stem cells, avoids tissue rejection problems. Ex. grow a new bladder.

48 DNA Technology: Applications 1. Basic Research 2. Medical 3. Forensics 4. Agricultural

49 Basic Research 1. DNA and protein studies 2. Evolution 3. Gene structure and control mechanisms.

50 Medical Uses 1. Diagnosis of Diseases 2. Gene Therapy 3. Vaccines 4. Pharmaceutical Products

51 Gene Therapy

52 Forensic Uses DNA fingerprints for crime solving used in every TV crime show DNA identification records standard for the military

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54 Comments Links suspect bodily to the crime scene, but doesn t prove they committed the crime. Results take MUCH longer than on TV shows. Analysis of old evidence is reversing some sentences.

55 Agricultural Uses 1. Animals Increased milk production Increased feed utilization Increased meat production

56 PharmAnimals

57 Agricultural Uses 2. Plants Herbicide resistance Retard spoilage of fruits Insect resistance BT corn Nitrogen-Fixation ability

58 Golden Rice

59 Genetically Modified Organism or GMO Produced by direct genetic manipulation, not traditional breeding practices. FDA has approved sale of GMO animal products for human consumption. Bioethics concerns

60 Future Of DNA Technology Cloning of higher animals. Stem Cells - growth of replacement tissues and organs. Gene therapy to correct DNA defects.?

61 Summary Know the basics of some of the DNA technology techniques. Know: Bacterial transformation lab (pglo) How Gel electrophoresis works Restriction enzymes