1. Chapter 13
Genetic Engineering

2. Selective Breeding
Allowing only the animals with desired characteristics to produce the next generation
Cats, dogs
Horses, cows
Potatoes,tomatoes

3. Hybridization
Crossing dissimilar individuals to bring together the best of both organisms
Luther Burbank (Botanist from Santa Rosa)
Disease resistant potato

4. Inbreeding
Continued breeding of individuals with similar characteristics
Dogs
Sometimes the cross brings together two recessive alleles for undesirable characteristics-joint deformities in German Shepherds and Golden Retrievers

5. Increasing variation
Breeders can increase the amount of variation by inducing mutations. Some will cause desirable characteristics. They then selecting individuals that carry the mutation and breed them
Uses chemical or radiation to induce mutations
Most useful with bacteria and plants
Bacteria that can digest oil
Polyploid plants (many sets of chromosomes) Makes the flowers and the fruit bigger and better looking

6. Manipulating DNA-Molecular Biology
Genetic engineering-making changes in the DNA code
DNA extraction-remove the nuclei from the rest of the cell
Density gradient centrifugation
Use detergent to dissolve the nuclear membrane, isolate DNA

7. Manipulating DNA-Molecular Biology
Genetic engineering (cont)
Cutting DNA-too big to be analyzed, so cut the DNA into smaller pieces with restriction enzymes, each specific to a certain sequence of DNA
Separating DNA-The cut up pieces (restriction fragments) can be separated according to size by gel electrophoresis . A current is passed through a gel that contains the DNA(like a molecular strainer, separates by size, small pieces travel faster)

8. Using the DNA sequence
After cutting and separating the DNA, the sequence can be read, and the sequence can be changed
To read the sequence:
The DNA is copied
In the copies, the A’s, T’s C’ and G’s at the end of each piece are tagged with different colored fluorescent dyes
Each copy is only partial, and each one is a little longer than all the others
The pieces are separated by length, and the detector then detects the different colors at the end of the sequences, and puts it all together like a nested puzzle to give the sequence

9. Using the DNA sequence Recombinant DNA
Takes a gene from one organism and puts it in another organism; e.g. human gene for insulin put into bacteria to make insulin for individuals with diabetes

10. Using the DNA sequence Copying the DNA-PCR Polymerase chain reaction
A reaction that replicates short strands of DNA
Can make millions of copes from a single molecule
uses a form of DNA polymerase that is active at high temps
The form of DNA polymerase was discovered in the hot springs of Yellowstone (“Taq”, for Themophilis aquaticus)
Invented by Kary Mullis, a professor at UCSC, and a surfer. Said he got the idea for the reaction while surfing

11. Cell transformation
A cell takes in DNA from the outside and the DNA becomes a part of that cell’s DNA
Bacteria, plant and animal cells

12. Cell transformation
In Bacteria, the introduced DNA joins into a DNA molecule in the bacteria called a plasmid
Plasmids occur naturally in bacteria
Plasmids often carry drug resistance genes
Plasmids have an origin of replication and a genetic marker, to allow it to be distinguished from other bacteria
often a drug resistance marker
the bacteria are grown in the presence of the antibiotic
the cells that don’t have the plasmid die, so it is a way of selecting
The gene encoded on the foreign DNA is expressed as protein in the transformed cell

13. Applications of Genetic Engineering
Transgenic organisms
Bacteria that produce insulin
Animal models to study human diseases and treatments for them
Plants that are resistant to weed killers

14. Cell transformation Plant Cells
A plasmid is used that causes tumors in plants
The transformed calls integrate the foreign DNA into their own chromosomes
The gene encoded on the foreign DNA is expressed as protein in the transformed cell

15. Cell transformation Animal Cells Can inject eggs with DNA
Other ways to trick the cells into taking up DNA
DNA may or may not integrate into cellular DNA
The gene encoded on the foreign DNA is expressed as protein in the transformed cell

16. Applications of Genetic Engineering
Cloning
Clone is a member of a population of genetically identical cells produced from a single cell
Sheep “Dolly”
An nucleus of an egg was fused with a cell taken from another adult. The embryo is placed in the uterus of another adult sheep.
The offspring, “Dolly”, was genetically identical to the original adult cell.