Post on 25-Dec-2015
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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
• http://www.techapps.net/interactives/pepperMoths.swf
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?