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TOPIC 4.4: GENETIC ENGINEERING AND BIOTECHNOLOGY

Topic 4.4: Genetic engineering and biotechnology

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Topic 4.4: Genetic engineering and biotechnology. Assessment Statements. 4.4.1 Outline the use of polymerase chain reactions (PCR) to copy and amplify minute quantities of DNA - PowerPoint PPT Presentation

Text of Topic 4.4: Genetic engineering and biotechnology

Topic 4.4: Genetic engineering and biotechnology

Topic 4.4: Genetic engineering and biotechnologyAssessment Statements4.4.1 Outline the use of polymerase chain reactions (PCR) to copy and amplify minute quantities of DNA4.4.2 State that, in gel electrophoresis, fragments of DNA move in an electric field and are separated according to their size4.4.3 State that gel electrophoresis of DNA is used in DNA profiling4.4.4 Describe the application of DNA profiling to determine paternity and also in forensic investigations4.4.5 Analyze DNA profiles to draw conclusions about paternity or forensic investigations4.4.6 Outline three outcomes of the sequencing of the complete human genome4.4.7 State that, when genes are transferred between species, the amino acid sequence of polypeptides translated from them is unchanged because the genetic code is universal4.4.8 Outline a basic technique used for gene transfer involving plasmids, a hose cell (bacterium, yeast, or other cell), restriction enzymes (endonucleases) and DNA ligase4.4.9 State two examples of the current uses of genetically modified crops or animals4.4.10 Discuss the potential benefits and possible harmful effects of one example of genetic modification4.4.11 Define clone4.4.12 Outline a technique for cloning using differentiated animal cells4.4.13 Discuss the ethical issues of therapeutic cloning in humansExploring DNADNA is at the very core of what gives animals and plants their uniquenessNew discoveries in genetic techniques include:Copying DNA (PCR)DNA revealing owners id (DNA Profiling)Mapping DNA (Human Genome Project)Cutting and pasting genes (gene transfer)Cloning cells and animalsExploring DNAThese new techniques offer new hope for:Treatment and vaccinesCreating new plantsFree or convicting people

Polymerase chain reactionPCR is a laboratory technique which takes very small quantity of DNA and copies all the nucleic acids in it to make millions of copies of the DNASolves a very simple problem-not enough DNA to analyzehttp://www.dnalc.org/resources/animations/pcr.htmlhttp://learn.genetics.utah.edu/content/labs/pcr/

Gel ElectrophoresisThis laboratory technique is used to separate fragments of DNA in an effort to identify its originEnzymes are used to chop up the long filament of DNA into varying sized fragmentsDNA fragments are placed into small wells (holes) in the gel which are aligned along one endThe gel is exposed to an electric current (positive on one side and negative on the other)

Gel ElectrophoresisThe effect is that the biggest , heaviest, and least charged particles do not move easily through the gelSmallest, least massive and most charged particles pass through the gel to the other side with little difficultyIn the endThe fragments leave a banded pattern of DNAhttp://learn.genetics.utah.edu/content/labs/gel/https://www.msu.edu/~russellr/portfolio/electrophoresis/electrophoresis.html

DNA ProfilingThe process of matching an unknown sample of DNA with a known sample to see if they correspond is call DNA profilingAKA DNA fingerprintingIf, after separation by gel electrophoresis, the:Pattern of bands formed by two samples of DNA fragments are identical, it means that both most certainly came from the same individualPatterns are similar, it means that the two individuals are most probably related

DNA ProfilingApplications of DNA profilingPaternity suitsMatch DNA to suspectDetermine how closely related species are to each otherDetermine evolutionHow DNA profiles are analyzedLook at page 102

Human genome project1990-started an international cooperative venture-Human Genome ProjectGoal: sequence the complete human genome2003-annouced they succeeded the projectScientist are working on deciphering which sequences represent genes and which do what

With genome libraries of genetic diseases, doctors can find out exactly where to look if they think one of their patients might possess a disease-carrying allele

Human genome projectOther Advantages:Produce new medications, Steps:Find beneficial molecules which are produced naturally in healthy peopleFind out which gene controls the synthesis of a desirable moleculeCopy that gene and use it as instructions to synthesize the molecule in a laboratoryDistribute the beneficial molecule as a new treatmentBy comparing the genetic makeup of populations around the world, countless details could be revealed about ancestries and how humans migrated and mixed their genes with other populations over timeGene TransferThe technique of taking a gene out of one organism and placing it in another organism is a genetic engineering procedure called gene transferIt is possible to transfer any species genes into another species makeupExample: proteins used by fish to resist the icy temperature of arctic waters are now produced by the modified tomatoes to make them more resistant to coldExample: corn, genetically engineered to produce toxins that kill the bugs which attack it (take protein from Bacillus thuringiensis)Cutting and Pasting DNAThe scissors used for cutting base sequences are called restriction enzymesRestriction enzymes called endonucleases find and recognize a specific sequence of base pairs along the DNA molecule (4 or 6 sets of base pairs)The endonucleases cut the DNA at the specific pointsIf both the beginning and the end of a gene are cut, the gene is released and can be removed from the donor organisms

Cutting and Pasting DNAFor pasting genes, the enzyme used is called DNA LigaseIt recognizes the parts of the base sequences that are supposed to be clicked together, called sticky ends, and attach them

http://www.dnalc.org/resources/animations/restriction.html

Copying dna (dna cloning)This is more complex because a host cell is needed in addition to the cutting and pasting enzymes. (most common- Escherichia coli)Some DNA is found in structures called plasmidsPlasmids are small circles of extra copies of DNA floating around inside the cells cytoplasmTo copy a gene, it must be glued into a plasmidPlasmid is removed from the host cell and cut open using a restriction endonucleases

Copying dna (dna cloning)To copy a gene, it must be glued into a plasmidPlasmid is removed from the host cell and cut open using a restriction endonucleasesThe gene to be copied is placed inside the open plasmidProcess called gene splicingThe plasmid is now called a recombinant plasmid and can be used as a vector, a tool for introducing a new gene into an organisms genetic makeup

Copying dna (dna cloning)In the final step needed for copying (or cloning) the gene.The vector is placed inside the host bacterium and he bacterium is given its ideal conditions to grow and proliferate.Done by putting the bacterium into a vat of nutritious liquid kept at a warm temperatureExample: Used to make insulinGenetically modified organisms (GMO)Is one that has had an artificial genetic change using the techniques of genetic engineeringOne of the main reasons is to be more competitive in food productionGenetically modified organisms (GMO)Transgenic plantsSimplest kind of GM food is one in which an undesirable gene is removedIn some cases, another more desirable gene is put in its place.First Example of GM Food1994-Flavr Savr tomato-genetically modified to delay the ripening and rotting processAnother tomato-able to grow in high salinity soilRice-engineered to produce beta caroteneGenetically modified organisms (GMO)Transgenic animalsHaemophilia-Factor IXUsing transgenic sheep

Is genetic engineering a good or a bad thingGenetic engineering raising many social or ethical questionsIs genetic engineering a good or a bad thingBenefits, promises, and hopes for the futureGM crops will help farmers by improving food productionGM crops which produce their own pest-control substances will be beneficial to the environment because fewer chemical pesticides will be neededUsing GMOs to produce rare proteins for medicines or vaccines could be, in a long run, less costly and produce less pollution than synthesizing such proteins in laboratoriesFarmers can be more in control of what crops or livestock they produce (selective breeding)The multinational companies who make GM plants claim that they will enable farmers in developing nations to help reduce hunger by using pest-resistant crops or GM plants which require less waterIs genetic engineering a good or a bad thingNo one knows the long-term effects of GMOs in the wildThere is a danger that the genes could cross speciesBt-crops which produces toxins to kill insects could be harmful to humans.The risks of allergies (may be allergic to one but not another)Critics are worried that large portions of the human food supply will be the property of a small number of corporationsHigh tech solutions are not necessarily better than simpler solutionsA proliferation of genetically modified organisms may lead to a decrease in biodiversityIs genetic engineering a good or a bad thingClones and cloningThe definition of a clone is a group of genetically identical organisms or a group of cells artificially derived form a single parentIn either case, the resulting cells or organisms were made using laboratory techniquesIn farming, clones have been made for decades for regenerating plant material or by allowing an in-vitro fertilized egg or divide to make copies of itselfCloning using a differentiated animal cell1996, a sheep by name of Dolly was bornFirst clone whose genetic material did not originate from an egg cellThis type of cloning is called reproductive cloning because it makes an entire individual

Cloning using a differentiated animal cellSteps to create DollyFirst the original donor sheep to be cloned, a somatic cell from the udder was collected and cultured. The nucleus was removed from a cultured cellAn unfertilized egg was collected from another sheep and its nucleus was removedUsing a zap of electrical current, the egg cell and the nucleus form the cultured somatic cell were fused togetherThe new cell developed in vitro in a similar way to a zygote and started to form an embryoThe embryo was placed in a womb of a surrogate mother sheepDolly was born, and was presented to the world as a clone of the original donor sheepCloning using a differentiated animal cellCloning using undifferentiated cellsTherapeutic cloning-simply to make copies of cellsAim is to develop cells which have not yet gone through the process of differentiationSince the first technique in this area involved using embryos, the cells are referred to as embryonic stem cells (stem cell research)Ethical issues surrounding therapeutic cloningSince therapeutic cloning starts with the production of human embryos, it raises fundamental issues of right and wrongIs it ethically acceptable to generate a new human embryo for the sole purpose of medical researchEthical issues surrounding therapeutic cloningMajor breakthroughs (current research):Growing skin to repair a serious burnGrowing new heart muscle to repair an ailing heartGrowing new kidney tissue to rebuild a failing kidney

Most researchers and medical professionals are against the idea of reproductive cloning in humans