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4.4 – Genetic e ngineering and biotechnology. Topic 4 - Genetics. Used to amplify small samples of DNA in order to use them for DNA profiling, recombination, species identification, or other research. Often very limited amounts of DNA are collected. PCR allows analysts to obtain
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4.4 – Genetic engineering and biotechnology Topic 4 - Genetics
Used to amplify small samples of DNA in order to use them for DNA profiling, recombination, species identification, or other research. • Often very limited amounts of DNA are collected. PCR allows analysts to obtain millions of copies of DNA. • REQUIRES: thermal cycler, primers, free DNA nucleotides, and DNA polymerase. Polymerase chain reaction
Heating in the thermal cycler denatures hydrogen bonds, exposing bases. • The mixture cools. Primers are added to the start of the target genes. • DNA polymerase replicates the DNA using complementary base pairing. • This cycle is repeated many times, until there are thousands of copies – enough to amplify even tiny samples found at a crime scene. * You do not need to know details of this method, but you can see how the technology has mimicked the natural process of DNA replication. The procedure…
PROCEDURE Below a scientist analyzes a DNA profile. • PCR to amplify DNA • Enzymes cut DNA in pieces of varying sizes • Add pieces to gel electrophoresis chamber • Electric currents runs through chamber (positive on one end & negative on the other) • Heavier fragments (least charged) stay closer to origin with smaller (most charged) fragments moving further • Banding pattern appears and can be compared Gel electrophoresis – DNA profiling
Paternity Crime When a sample of DNA is taken from any number of sources at a crime scene a DNA profile can be compared to that of suspects In this case, the analyst would be looking for a complete match • When a parent is in question a DNA profile is used • In this case, the analyst would be looking for a number of shared bonds Uses of DNA profiling
*The overlapping bands between the victim and perpetrator suggest a close relationship
*DNA evidence is being reviewed in many wrongful conviction lawsuits
Explain how biotechnology is used to determine the identity of a criminal from a small blood sample left at a crime scene. (8 marks)
DNA evidence is better at proving innocence than guilt.*DISCUSS
GENOME: the entirety of an organism’s hereditary information. Human Genome Project was an international cooperative endeavor to record the entire base sequence of the human genome. • It was completed in April of 2003 It accomplished: • The number and loci of all the genes in our genome were found (~30,000) which has led to targeted research in diagnostics, treatment, and pharmacology. • Many new proteins and their functions were discovered. • DNA comparisons can be made with other species and we can find out a lot more about the evolutionary history of us and other species. • Bioinformatics was born – high tech way to collect, collate, and access information from genetic databases. Human Genome Project
GENE TRANSFER http://www.livescience.com/20647-favorite-genome-sequence-studies.html http://www.livescience.com/16752-gfp-protein-fluorescent-nih-nigms.html
THERAPEUTIC REPRODUCTIVE Remove a differentiated diploid nucleus from individual to be cloned. Enucleate a donor egg cell. Insert the diploid nucleus into the enucleated cell. Implant into the endometrium of a surrogate and gestate. The newborn will be genetically identical to the nucleus parent. * EX. Dolly the sheep. • Remove a differentiated diploid nucleus from the cell to be cloned. • Enucleate a donor egg cell. • Insert the diploid nucleus into the enucleated egg cell. • Stimulate it to divide and grow in vitro. • The resulting embryo is a risk source of stem cells which can be harvested or cultured. • The outer layer of cells is removed, so only the inner cell mass is used to culture the tissues needed. Reproductive vs Therapeutic Cloning
REPRODUCTIVE THERAPEUTIC Uses: Create stem cells for transplants, such as in burns patients or leukemia. Replace other damaged tissues such as nerves, pancreas cells, etc. Much reduced risk of rejection of cells as they are genetically identical to the recipient. • Dolly was the result of many attempts. • She died young but of age-related illnesses. • Human reproductive cloning is illegal. Reproductive vs Therapeutic Cloning
Ethics of Therapeutic CloningTherapeutic cloning is the center of much debate. In part this is due to pre-conceived notions of cloning from the media and fiction. However, the root of much of the debate lies in the fact that the created embryos could potentially be implanted into a surrogate mother and develop into a human fetus.