1. Chapter 13
Genetic Engineering

2. Selective Breeding Where did all the breeds of dogs come from?
Humans bred dogs to have certain traits, breeding dogs that had the best versions
Selective breeding only allows the traits we want to be passed down to the next generation
Hybridization is crossing different organisms with two different desirable traits
Disease resistance plant crossed with food- producing capacity plant

3. Dog Breeds

4. Selective Breeding
Inbreeding is the continued breeding of organisms with similar characteristics
Maintains desired characteristics
Only allowing a dog to mate with another of its own breed
Can increase the likelihood of genetic defect/disease

5. Increasing Variation
Breeders can increase variation by inducing mutations, which are the ultimate source of genetic variability
Mutations are inheritable changes in DNA
Occur spontaneously or increase chance through chemicals and radiation
Most are harmful, a few can be desirable
Most useful in bacteria
Used to create polyploidy (extra chromosomes) in plants, which is less harmful to plants

6. Manipulating DNA
Genetic engineering is making changes in the DNA code of a living organism
Remove the code
Read the code
Change the code
Replace the code in the organism

7. Manipulating DNA
Removing the code: extraction; DNA is separated from the other parts of the cell
Extraction of DNA is done by rupturing the cells and adding a precipitating reagent such as ethanol, then DNA can be spooled onto a glass rod or sucked out with a pipette.
Cutting DNA into pieces is done with restriction enzymes; each one cuts DNA at a specific sequence of nucleotides.

8. Manipulating DNA
Separating DNA can be achieved by using gel electrophoresis
The cut DNA is put into the well at one end (negative end – black) of the gel. DNA molecules are negatively charged and will travel to the positive end when current is applied
Smaller fragments travel faster; separates DNA fragments based on size
Used to create a genetic “fingerprint” or help isolate a gene

9. Gel Electrophoresis

10. Manipulating DNA
Reading the DNA occurs by tagging some bases while copying the DNA, the colored tags help determine the order of bases
Polymerase chain reaction makes copies of a particular gene

11. Cell transformation
Transformation is the process of a cell taking outside DNA and incorporating it into its own
Transgenic organisms are organisms with foreign DNA
E.coli is used daily as a transgenic organism to produce human drugs, ex. human insulin and TPA (clot buster for heart attacks)
Bacteria make great transgenic organisms because they have a tiny circular DNA, called a plasmid

12. Bacterial Transformation

13. Cell Transformation
Foreign DNA is joined to the plasmid, plasmid DNA ensure that the sequence will be replicated
Plasmid also has a label (genetic marker) so can distinguish if it has the gen
Transforming plant cells involve using a bacteria that inserts a small DNA plasmid into the plant (normally causing tumors)
Scientists inactivate the tumor gene, and use the bacteria to deliver the gene of interest

14. Transgenic Organisms
Plants are important transgenic organisms. In the year 2000, 52% of soybeans, and 25% of corn grown in the US were transgenic (or genetically modified); most were modified for pesticide resistance
Animals also being used, like the cow that makes milk with a human protein
Modify mice to have immune systems to act like humans
Animals the produce more growth hormone so they grow faster

15. Transgenic Cows
humanized-milk-safe.html

16. Manipulating DNA
Cloning – making a genetically identical organism from a single cell. In 1997, Ian Wilmut cloned, the now deceased, Dolly from the mammary cell of a sheep
Gene therapy – using genes to treat diseases, such as cystic fibrosis
Genetically modified organisms (food) – altered so less pesticides are needed

17. Dolly and Bonnie

18. Stem Cells Stem cells are unspecialized cells (not differentiated)
All body cells have all the DNA, but only use the genes to make the proteins needed for that cell type once it becomes specialized
Types: embryonic, amniotic, adult