Biotechnology. Chapter 17 section 1 (only)

Transcription

1 Biotechnology Chapter 17 section 1 (only)

2 Learning Goals for Today: Explain how DNA profiling can identify individuals Interpret data from DNA electrophoresis Discuss genetically modified organisms Explain some ways DNA can be recombined in nature

3 What Is Biotechnology? Biotechnology is the use of organisms, cells, or biological molecules to produce food, drugs, or other goods Yeast: fermentation (10,000 years ago) Selective breeding of animals/plants (between 6 and 15,000 years ago) cloning genetic engineering Finger-printing Genome sequencing Diagnosing and treating diseases

4 Is all this natural? Merriam Webster s definition of natural: being in accordance with or determined by nature

5 According to nature Corn Lemon Banana Dog Pig

6 Things that we assume com straight from nature, do not!

7 ALL dogs come from the wolf!

8 All these veggies come from wild mustard!

9 Genetically Modified Organism (GMO): an organism that contains foreign DNA w/ altered characteristic(s) does not occur naturally because the selection pressure in for human benefit obtained via cloning technology 9

10 Genetic engineering Recombinant DNA - combining DNA molecules not found together in nature; via cloning

11 How Does DNA Recombine in Nature? Bacteria and yeast: can take in DNA from the environment Transformation DNA piece can come from a the same or a different species

12 Transformation in Bacteria (a) Bacterium bacterial chromosome plasmid bacterial chromosome bacterial chromosome 1 micrometer Bacteria can take in DNA from their environment DNA fragments plasmid New DNA might code for anything A DNA fragment is incorporated into the chromosome (b) Transformation with a DNA fragment The plasmid replicates in the cytoplasm (c) Transformation with a plasmid Big Issue: Genes for antibiotic resistance Fig. 13-1

13 Viruses Also Transfer DNA virus viral DNA 1 A virus attaches to a susceptible host cell host cell host cell DNA 2 The virus enters the host cell 3 The virus releases its DNA into the host cell; some viral DNA (red) may be incorporated into the host cell s DNA (blue) viral DNA recombinant virus viral proteins 6 The host cell bursts open, releasing newly assembled viruses; if recombinant viruses infect a second cell, they may transfer genes from the first cell to the second cell 5 New viruses assemble; some host cell DNA is carried by recombinant viruses 4 Viral genes encode the synthesis of viral proteins and viral gene replication; some host cell DNA may attach to the replicated viral DNA (red/blue combination) Fig. 13-2

14 Genetic Engineering Recombinant DNA - combining DNA molecules not found together in nature; via cloning Molecular cloning (DNA cloning) Types of Cloning Manipulating a small piece of DNA, typically using bacteria as host Therapeutic cloning Creating stem cell lines with same DNA as a patient, used for treating diseases and disorders Reproductive cloning Technique used to generate an animal with exact genetic makeup (DNA) as another animal

15 DNA Cloning what is it? Molecular cloning Inserting foreign DNA from one organism into another 15

16 Bacteria can transfer DNA into plants Agrobacterium infects plants Physically injects part of its own DNA into the plant cell Plant will grow a gall at the infection site Bacteria live in the gall Plant synthesizes nutrients for the bacteria Similar process with Rhizogenes bacteria but the end result benefits the plant

17 Agrobacterium is a natural, and commonly used, plant genetic engineer

18 The gene gun is also used to introduce DNA into cells

19 After cells are modified, they are induced to regenerate into whole plants

20 Where are GM foods? The Marketplace 60 to 70% of processed food contains GMO In the US: Corn ~45% is GM Soybean ~85% is GM Cotton ~76% is GM Canola ~60% is GM 20

21 Biotech crops widespread, rapidly adopted: Grown on >10% arable land on planet, extensive uptake in developing world

22 Four crops dominate, 8+ crops in USA

23 Two traits dominate worldwide

24 Newly approved GE crop varieties in USA Soybean insect resistant (Apr. 2014) Alfalfa reduced lignin (Nov. 2014) Potato reduced black spot bruise and low acrylamide production (Nov. 2014), reduced browning and disease resistant as well (August 2015) Soybean and cotton new herbicide tolerances (Jul Jan. 2015) Apple non-browning (Feb. 2015) Plum virus resistant (2014)

25 Non-browning Arctic Apple Reduced spoilage/waste, improved quality USDA approved Courtesy of Jennifer Armen, Okanagan Specialty Fruits, Canada

26 Non-browning Arctic Apple Time lapse video

27 Innate potato approved reduced browning and acrylamide ( waste, safety)

28 Innate potato in my hands for teaching One hour after cutting Control vs. Innate Two days after cutting Innate vs. Control

29 Innate potato 2.0 late blight resistant, reduced acrylamide, reduced sprouting and browning ( waste, safety, pesticide, yield)

30 Dramatic change in color of chips, highly prized by consumers Provided by Walter De Jong, Cornell University

31 Resistance transgenes promising solution/s to devastating citrus greening Scientific American March, 2013

32 Face the wall of opposition?

33 Defensin-like proteins from spinach for citrus greening disease resistance Courtesy of Eric Mirkov, Texas A & M

34 Helping forests: American Chestnut restoration by genetic modification March 2014 issue - Scientific American

35 Forest health a major and growing concern

36 Diverse pipeline of biofortification products = enhancement of critical vitamins or nutrients Many more examples funded by Gates Foundation / other sources

37 Biotech methods useful where breeding is ineffective or slow Rice Cassava Sorghum Banana Rice Cassava

38 Management of monocultures Mismanagement promotes the proliferation of weeds resistant to herbicides and bugs resistant to pesticide Many weeds have developed resistance to glyphosate (RoundUp) Rootworms have also developed resistance to Bt Herbicide can kills plants that are not weeds Milkweed supplies Monarch butterflies eat Rotating crops, eliminate volunteers, and creating havens with no pesticide

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40 Cloned Stem Cells Immune system will recognize & destroy cells with different DNA Therefore, stem cells need to contain same DNA as patient Cloned Stem Cells - Therapeutic Cloning Somatic Cell Nuclear Transfer Somatic cells = all body cells Nucleus = region of cell containing DNA Transfer = remove and replace

41 Somatic Cell Nuclear Transfer

42 Induced Pluripotent Stem cells (ipscells) Reprogramming somatic cells (skin) so they behave as stem cells Can replace embryo harvesting Human cloning not needed Used for therapeutic cloning Must add new proteins (transcription factors) to reprogram NE

43 How Is Biotechnology Used in Forensic Science? DNA identification: huge role in criminal investigations Individual have unique DNA sequences DNA fingerprint How to we figure out a person s DNA fingerprint?

44 Differences in short tandem repeats (STRs) can identify individuals by their DNA STRs: noncoding DNA STRs are not transcribed into mrna Short sequence of 2-5 nucleotides Repeated many times (up to 50) All in a row (in tandem) Number of repeats varies (different alleles)

45 Example of a STR Eight side-by-side (tandem) repeats of the same four-nucleotide sequence Fig. 13-4

46 Using STRs to Identify Individuals Different people may have different alleles of the STRs Allele: number of repeats U.S. Department of Justice 13 standard STRs tested Over a trillion possible combinations of alleles Exact match needed for conviction

47 DNA fingerprinting is very useful Paternity/mate rnity testing Criminal investigations Should there be a national database of everyone s DNA? Question for Thought:

48 How do we figure out someone s DNA fingerprint? DNA sequence cannot be read directly Sequencing entire genomes is expensive and takes time Sometimes there isn t much DNA in the sample PCR: a technique for making lots of DNA copies of specified pieces of DNA

49 PCR: the Polymerase Chain Reaction Modern version developed by Kary Mullis Only need a tiny amount of starting DNA Makes lots of copies of DNA of interest DNA Learning Center, Cold Spring Harbor Laboratory

50 Gel electrophoresis: a method to examine PCR results After PCR: a lot of pieces of DNA Often alleles are different sizes Gel electrophoresis: a method to separate DNA based on size

51 Number of repeats Example of DNA Profiling for one STR D16: An STR on chromosome DNA samples from 13 different people Why do some people have 1 band and some people have 2 bands?

52 STR name DNA Profiling Penta D CSF D16 D7 Fig. 13-7

53 Mutations Substitutions or point mutations Insertions Deletions Inversions Translocations Due to errors during replication (1 in 100,000, but proof-reading fixes 99%) or external factors like toxins and radiation

54 Mutations in STRs STRs: Sequence Tandem Repeats (forensics) Errors are due to replication slippage Slippage occurs in STRs about 1 per 1000 generations

55 Replication slippage

56 Other uses for gene sequencing Genes other than the STRs are often sequenced Health-related tests Studying gene function