Chapter 13 Genetic Engineering Selective Breeding- choosing what parents you want to produce offspring for the next generation. What do get when you cross a bull dog and a shitzu? Hybridization- Crossing dissimilar individuals to bring together the best of both organisms. Hybrid Vigor- phenomenon, offspring are better than the parents.
Inbreeding is the continued breeding of individuals with similar characteristics. –Risky, because it could bring out the recessive alleles and cause a genetic defect. Blindness, joint problems
Increase Variation Why would humans want to increase variations? –Better the species –Make the mutation occur faster –More variety
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Manipulating DNA Scientist change DNA by –Extracting DNA from cells –Cut into smaller pieces –Identify the sequence of bases on the DNA molecule –Make unlimitied copies of DNA
DNA Extraction Cells are opened up and DNA is separated from other parts of the cell
Cutting DNA DNA is cut into small fragments by restriction enzymes. (Cuts DNA at a specific nucleotide sequence…very precise)
Separating DNA Gel Electrophoresis- DNA Fragments are placed in certain gel wells and an electric voltage is passed through them. DNA molecules move toward the opposite end of the gel. Smaller DNA fragments move faster through the gel.
Using the DNA Sequence The DNA Sequence can be read, studied, or changed. Compare genes with other organisms. Recombinant DNA- produced by combining DNA from different sources.
Making Copies In order to study genes, it helps to make copies. PCR (Polymerase Chain Reaction)- makes many copies of DNA through a process of heating and cooling using DNA polymerase.
13.4 Applications of Genetic Engineering Transgenic Organisms- organisms contain genes from other organisms. –Example: The enzyme (luciferase) from fire flies was transferred into a tobacco plant cell. –What do you think happens? The plant glows at dark…page 331
Why make transgenic organisms? Resist pests, herbicides, harsh conditions Improve nutritional value, shelf life Test and study Medical purposes…insulin, growth hormone, clotting factors Transgenic Animals can produce more milk, less fat, human proteins
Cloning Cloning is producing genetically identical cells from a single cell. –Bacteria is easy to clone (unicellular) –What about multicellular organisms? –Ian Wilmut cloned the first sheep. DOLLY.
Cloning Process
To Clone or Not to Clone?