1. Warm-Up #33
Answer questions #1-5 on Text page 321, Section Assessment.

2. Daily Quiz #22
Name two methods used by breeders to increase the rate of mutation.
Biologists use _______ to cut the DNA molecules at a specific sequence of nucleotides to make smaller fragments.
True or False: The pattern of colored bands on a gel tells the exact sequence of bases in DNA.

3. Changing the Living World and Manipulating DNA
Genetic Engineering
Changing the Living World and Manipulating DNA

4. Selective Breeding
Allows only those traits that are desirable for a certain organism to pass on to the next generation.
Burbank potato
Hybridization—crossing dissimilar individuals to get the best of both
What is the benefit? Give an example
Inbreeding—continued breeding of individuals with similar characteristics
What are the benefits? What are the risks?

5. Increasing Variation
Breeders can increase the genetic variation in a population by inducing mutations, which are the ultimate source of genetic variability.
Can use radiation and chemicals
Bacteria
Millions of organisms at one time, radiation and chemicals, higher chance of beneficial mutation
Plants
Drugs that cause nondisjunction
Polyploidy

6. Manipulating DNA
Scientists can use their knowledge of the DNA structure to make unlimited copies of DNA and make changes to the DNA. This process of genetic engineering use the following processes
DNA extraction
Cutting DNA
Separating DNA
Reading the sequence
Cutting and Pasting
Making Copies

7. DNA Extraction
Open the cells and separate the DNA from the other cell parts by a simple chemical procedure.

8. Cutting DNA
DNA molecules from most organisms are too large to be studied as a whole, so they cut them into precise small fragments using restriction enzymes.
Restriction Enzymes are very precise, and cut DNA at a specific sequence of nucleotides.
Lock and Key—a particular restriction enzyme will only cut a DNA sequence if matches precisely.
EcoR I—Figure 13-5
Leaves “Sticky Ends”—can attract complementary sequences

9. EcoR1

10. Separating DNA Gel Electrophoresis
The cut DNA fragments are poured into wells on a gel (thick piece of gelatin)
An electric current is passed through the gelatin—causing the DNA fragments to move toward the opposite end.
Longer strands move more slowly and do not migrate as far as smaller strands.
The pattern can be used to compare the gene composition of different organisms or different individuals.

11. Gel Electrophoresis

12. Reading the Sequence
A complementary DNA strand is made using fluorescent nucleotides.
DNA polymerase adds these nucleotides to the DNA fragments in the gel.
When a fluorescent nucleotide is added, replication stops.
The mixture of fragments can then be separated on a gel.
You can then read the sequence on the gel. Each base has a different color.
The order of the colored bands tells the exact sequence of the bases in the DNA

13. DNA Sequencing

14. Cutting and Pasting This process is used to change DNA.
Short sequences can be assembled using DNA synthesizers.
DNA can then be spliced together. Synthetic DNA can be combined with an organisms original DNA or you can combine DNA from different organisms
Recombinant DNA—combination of DNA from different sources.

15. Making Copies Polymerase Chain Reaction (PCR)
Add primers to each end of the chain you want to copy (a complementary strand)
Heat DNA to separate the strands (create a bubble)
DNA polymerase makes copies of the regions between the strands.
The copies then serve as templates to make more copies.
A few dozen cycles can produce millions of copies of DNA.

16. DNA Fingerprinting Lab

17. Homework—Due Tuesday 12/14
Read Text
Be sure DNA Fingerprint Lab is complete
Study Guide 94, 94a and 95