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Abraham Lincoln – Marfan Syndrome Emily Dickinson – Manic Depression

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Presentation on theme: "Abraham Lincoln – Marfan Syndrome Emily Dickinson – Manic Depression"— Presentation transcript:

1 Abraham Lincoln – Marfan Syndrome Emily Dickinson – Manic Depression
Vincent Van Gogh – Epilepsy Albert Einstein – Dyslexia John F. Kennedy – Addison’s Disease Rita Hayworth – Alzheimer’s Disease Ray Charles – Primary Glaucoma Stephen Hawking – Amyotrophic Lateral Sclerosis Of course you may not have been born!

2 Chapter 13 – Genetic Engineering
Section 13-1: Changing the Living World

3 Humans have been able to control different species of organisms through several methods
Selective breeding = a method of breeding that allows only those individuals with desired characteristics to produce the next generation

4 Most domestic animals (dogs, cats, llamas, other farm animals) and crop plants have been produced through selective breeding Selective breeding helped develop disease resistant crops to help food production

5 Hybridization = crossing dissimilar individuals to bring together the best of both organisms
This technique was often used to develop those disease resistant crop strains Hybrids are usually hardier than the parents and contain a mix of traits

6 Inbreeding = the continued breeding of individuals with similar characteristics
This technique is used to maintain desired characteristics in a line of organisms Ex. Many dog breeds are maintained by inbreeding Inbreeding does have risks  since the individuals are genetically similar, individuals could inherit recessive alleles resulting in defects (blindness, joint deformities)

7 While humans have worked to control some species, they have also been able to increase variation as well Breeders can increase the genetic variation in a population by introducing mutations, which are the ultimate source of genetic variability

8 Breeders can increase mutation rates by using radiation or chemicals
Scientists have produced many useful strains of bacteria using this method; ex. Bacteria that can digest oil could help to clean oil spills Scientists have also been able to use this technique to create polyploidy plants (extra sets of chromosomes) which are usually larger and stronger

9 Section 13-2: Manipulating DNA

10 Random mutations have a variety of results, both good and bad, but science has figured out how to methodically change DNA Different techniques are used to extract DNA from cells, to cut DNA into smaller pieces, to identify the sequence of bases, and to make unlimited copies of DNA

11 Genetic engineering = making changes in the DNA code of a living organism
DNA extraction has become easy  the cells are opened and the DNA is separated from the other cell parts

12 In order to analyze DNA, it needs to be cut into smaller pieces
Restriction enzymes = enzymes that cut DNA at a specific sequence of nucleotides Hundred of restriction enzymes are know and used as tiny scissors to cut DNA They are very precise and will only cut a DNA sequence if it matches exactly (like a lock and key)

13 Once DNA is cut into smaller pieces, it can be separated to be analyzed
Gel electrophoresis = a method of DNA separation in which a mixture of DNA fragments are placed at one end of a porous gel, and an electric voltage is applied

14 When the power is applied, the negatively charged DNA fragments start to move to the positive end of the gel (opposites attract) Smaller pieces move faster and farther This method can be used to compare gene composition or even identify 1 particular gene

15 Knowing the sequence of an organisms DNA allows scientists to study specific genes and figure out functions and specific gene combinations In order to “read” DNA, scientists need a way to figure out the sequence of bases

16 They are able to use DNA polymerase to replicate an unknown strand
They make many copies of the DNA – each one at a different length with a different dye on it By separating the different length strands, they can determine the order of bases

17 Scientists have determined a way to cut and paste DNA
Short pieces of DNA can be made by a lab machine (DNA synthesizer) Enzymes that splice DNA together can be used to combine different pieces of DNA Recombinant DNA = DNA that have been produced by combining DNA from different sources

18 A technique known as polymerase chain reaction (PCR) allows scientists to make many copies of DNA to be studied PCR is like a copy machine for DNA Short segments are added to the beginning and end of DNA  these are primers because they get the DNA ready to by copied by DNA polymerase DNA is heated to separate the 2 strands  then DNA polymerase and nucleotides are added and many copies get produced

19 Section 13-3: Cell Transformation

20 What good would it do to modify DNA if it weren’t possible to put it back into a living cell and make it work? During transformation, a cell takes in DNA from outside the cell  this external DNA becomes a component of the cell’s DNA Griffith was able to demonstrate this with his pneumonia bacteria  suggesting that bacteria can be transformed simply by placing them in a solution containing DNA

21 Transforming bacteria
Plasmid = a small circular DNA molecules Plasmids are useful because they have DNA sequences that promote replication Plasmids also have genetic markers that make it possible to tell if the bacteria has the plasmid (genes resistant to antibiotics are commonly used)

22 Foreign DNA gets joined to the plasmid and the plasmids are added to cultures of bacteria
Bacteria cells take up the plasmids and get transformed If the antibiotic resistance is used as a genetic marker, those cells that were transformed are the only ones that survive when treated with the antibiotic

23 Transforming plant cells
There are certain bacteria in nature that contain plasmids that infect plants and cause tumors Scientists have figured out how to swap out the tumor causing DNA for foreign DNA The plasmid can now be used to infect plants and transform them instead of cause tumors

24 Transforming animal cells
Many egg cells are large enough to inject DNA directly into the nucleus Once in the nucleus, the enzyme that helps repair DNA may help insert the foreign DNA

25 Applications of Genetic Engineering
Section 13-4: Applications of Genetic Engineering

26 Genetic engineering has spurred the growth of biotechnology, which is a new industry that is changing the way we interact with the living world Transgenic organisms are organisms that contain genes from other species

27 Transgenic bacteria now produce many important substances useful for health and industry
Bacteria transformed with human genes can be used to make proteins such as insulin, growth hormone, and clotting factors This makes it much easier and cheaper to treat certain diseases

28 Transgenic animals have been used to study genes and to improve food supply
Mice have been produced with human genes to make their immune systems similar to humans  this allows scientists to study the effects of diseases on the human immune system Livestock have been produced with extra growth hormone so that they can grow faster and produce leaner meat Eventually, transgenic animals may be able to provide us with supplies of human proteins

29 Transgenic plants are now an important part of the food supply
Many plants have been transformed with a gene to produce a natural pesticide Other plants have genes that make them resistant to weed killers Eventually, transgenic plants may be able to produce human antibodies for fighting disease and other purposes

30 A clone = a member of a population of a genetically identical cells produced from a single cell
Cloning bacteria and other microorganisms has been easy to do Scientists were able to prove they could clone multicellular organisms Dolly (a sheep) was the first clone and was even able to reproduce

31 Researchers hope cloning will let us make copies of transgenic animals and help save endangered species The technology is controversial because studies show that cloned animals may suffer from a number of genetic defects and health problems

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