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Published byEvangeline Rose Modified over 9 years ago
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Genetic Engineering
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Selective Breeding Have you ever seen a dog show on tv? How many different types of dogs were there?!
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Selective Breeding We know all the dogs are the same species o So how did we end up with so many different breeds?! Selective Breeding – allowing only animals with desired characteristics to produce the next generation
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Selective Breeding People use selective breeding to pass desired traits on to the next generation
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Hybridization Hybridization – crossing dissimilar individuals to bring together the best of both organisms o The offspring are usually hardier o May include a fast growth rate with a resistance to a particular disease
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Selective Breeding
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Inbreeding When it comes to dogs and cats, we found particular traits we desired most We continued to breed these animals to produce more with similar traits Inbreeding – continued breeding of individuals with similar characteristics
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Variation Variation exists in nature and is the key to the survival of a group of organisms o Imagine…everyone in this room was severely allergic to bee stings o Now, we drop a bee’s next right in the middle of the room o What would happen?!
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Variation The bee allergy was an extreme example but you get the point Populations need variation! Breeders can increase the genetic variation in a population by inducing mutations, which are the ultimate source of genetic variation
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Variation in Bacteria Bacteria reproduce very quickly! This allows bacteria to evolve rapidly Scientists have created useful “mutant” bacteria to do many jobs!
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New Plants Scientists can use drugs that prevent chromosome separation during meiosis Polyploidy – when a cell has many sets of chromosomes o Animals usually die of this condition but plants can survive o Often creates larger and strong plant species
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Polyploidy
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Manipulating DNA Genetic Engineering – making changes to DNA sequence Scientists can remove DNA from a cell, make copies and alter the sequence to what they wish!
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Manipulating DNA In order to make copies of DNA scientists use a technique called polymerase chain reaction PCR – technique used to copy DNA
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Manipulating DNA First the DNA must be extracted o Cells are broken open, proteins are broken down and DNA is removed Then the DNA is cut using restriction enzymes, which cut DNA at specific sequences
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Gel Electrophoresis Scientists must then separate the DNA to be analyzed Gel Electrophoresis – DNA fragments are placed in one end of a porous gel and an electric voltage is applied to the gel. Smaller particles move faster.
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Gel Electrophoresis DNA is usually dyed with a fluorescent marker to make it more visible
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How is this Useful!? Knowing the sequence of DNA allows scientists to do some pretty incredible things! o Study specific genes o Compare genes of other organisms o Helps researchers discover the functions of genes o Can help to prevent or cure diseases
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Transformation Transformation – when a cell takes DNA from outside the cell and integrates it with its own DNA Very easy to do with bacteria o Bacteria readily accept plasmids, simple circular structures containing recombinant DNA
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Transgenic Organisms Transgenic – containing genes from other organisms o Genetic engineering has improved biotechnology Transgenic tobacco plant Contains genes from a firefly! Transgenic tomatoes Ripening gene has been turned off so the tomatoes have a longer shelf life
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Cloning A clone is a genetically identical organisms created from a single cell. In 1997, Ian Wilmut was the first scientist to clone a mammal o Dolly the sheep was the first mammal to be successfully cloned!
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GMOs Genetically Modified Organism o Good or bad? o Safe? o How far should we take it?
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