biotechnology chapter 13. selective breeding w done for thousands of years w “farmer brown” w...
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BIOTECHNOLOGYChapter 13
Selective Breeding Done for thousands of years “Farmer Brown” Produce desirable traits “mother nature” to alter genes Requires time
1. Inbreeding - Crossing similar genotypes
Closely related Maintains desirable traits Produces undesirable traits Done with horses, dogs, cattle,
plants
Golden Retriever Puppies
If inbreed incorrectly may have problems with hip dysplasia, ears, eyes….
2. Hybridization- Crossing different genotypes Combines desirable traits of
both parents “hybrid vigor” - healthier offspring Offspring usually sterile Horses + donkeys = mule
Sweet & Hardy Corn
Most crop plants have been hybridized for certain traits.
Traits like : more vitamins, certain colors/flavors, larger, won’t freeze…
3. Mutations
Are changes in DNA
Ultimate source of variation!
Occur unexpected & randomly
Scientists speed up mutations by exposing organisms to chemicals or radiation
Radiated to produce small or no seeds Seedless Oranges
Drawback – loose flavor
Genetic Engineeringgrowing field of careers
Technique used to identify and/or alter genes at the molecular level
Faster method Requires equipment, money
Genetic engineering
1. DNA fingerprinting by gel electrophoresis
2. PCR amplifies DNA3. Transformation of DNA
• Transgenic organisms• GMO foods• Cloning
DNA fingerprinting
An identification system for individuals
A unique pattern of bands that represent segments of a person’s DNA
The process is known as gel electrophoresis
•DNA is cut into segments with restriction enzymes
•DNA is poured into agarose gel and electric current is added
•DNA segments travel across gel and appear as bands when dye is added
How does it work ? ? ?
How they are used Scientists look for matching bands
1. Comparisons with crime scene sample can ID individuals as guilty or innocent
2. Paternity testing
Suspect #1
Suspect #2
Crime scene evidence
Who is the father?......
Child F1 F2 F3 F4
Cell Transformation
DNA from one organism is taken into another (sometimes unrelated) organism
Tools required:1.Restriction enzymes to cut
DNA at specific sites2.Vectors - “DNA taxis” to
move the gene ( virus or plasmids)
Restriction Enzymes
Recognize DNA palindromes ex: RACECAR
Cut at specific sites
How Restriction Enzymes Work
Plasmid Vectors Small circular pieces of bacterial DNA Sections of DNA can be:
• removed• manipulated •reinserted by “gluing” back into DNA using the base pairing rule!
Plasmid Vectors
Producing a Trangenic Organism
Applications of DNA Technology
Transgenic bacteria
•“Ice minus” gene, nitrogen fixing gene
•“oil eaters”•HGH, insulin, interferon
Transgenic plants
• resistant to herbicides• produce own pesticide• more protein• prevent rotting• more nutritious
Broccoflower and Purple
Cauliflower
Aggie Beta-sweet Carrot
Transgenic animals
• cows with more milk• goats, pigs, cows with human
proteins•cow milk with missing enzymes•cloning
+ =
“silk milk” = light weight with steel strength
Cloning
Donated egg has nucleus removed Fertilized using electricity with a
diploid body cell Implanted into surrogate mother to
grow and develop
History of Cloning
>>click on diagram to connect to internet
Gene Therapy
changing a gene that causes a genetic disorder
The bad gene is replaced with a working gene that makes the needed protein
Ex: Cystic Fibrosis inhalers
Homework
Read the article on page 330 Write answers to #1 & #2