1. DNA Technology

2. Biotechnology
Biotechnology is using other organisms to make a specific product
Selective breeding chooses plants or animals with certain traits and then allows them to breed

3. Test Crosses
Test crossing is used to determine the genotype of a dominant phenotype Example: You want to make all purple-flowered plants. You don’t know if your parent plant is homo- or heterozygous. How do you find out?

4. Test Crosses
You must cross your purple plant with a white plant. Why? White is recessive, so it has a known genotype (pp). There are two possible outcomes:

5. Test Crosses Genotypes all Pp Phenotypes all purple Outcome a. PP x pp

6. Test Crosses
Outcome b. Pp x pp Genotypes ½ Pp, ½ pp Phenotypes ½ purple, ½ white P p Pp pp
What does is mean if you get recessive offspring?

7. Applications of DNA Technology
Genetic Engineering is the moving of genes from one organism to those of another

8. Applications of DNA Tech.
Industry examples
Bacteria are used to:
break down pollutants
produce cheese, detergent, paper products
extract minerals from ores
make chemicals like indigo and phenylalanine

9. Applications of DNA Tech.
Medical examples
Bacteria are used to produce hormones, proteins, and vaccines
Human diseases can be studied in other animals (like mice)

10. Applications of DNA Tech.
Agriculture examples
Plants are resistant to frost, pesticides, insects (Bt crops)
Plants are made with more vitamins in them (golden rice)
Plants can be made non-
allergenic

11. Restriction Enzymes
Restriction Enzymes are one of the tools used in genetic engineering
The enzymes cleave or digest (cut) DNA into smaller pieces
The enzymes look for specific locations in the DNA sequence

12. Restriction Enzymes Most of the recognition sequences are palindromes
The enzyme will cut at a specific point within the sequence

13. Restriction Enzymes Many times a staggered cut is made
This produces “sticky ends” that can readily combine with other cut pieces of DNA

14. Bacterial Transformation
Recombinant DNA is formed by combining DNA from two different sources

15. Making Recombinant Plasmids
Isolate the gene of interest (ex. human insulin)
Isolate bacterial plasmid (a small circular piece of DNA)
Cut both types of DNA with the SAME restriction enzyme
You will get matching sticky ends

16. Mix the two types of DNA together
(gene splicing)
Add the enzyme DNA ligase to permanently bond the pieces
Insert the plasmid into a host bacterial cell

17. Getting the recombinant plasmid into a host cell is not easy.
Gene gun can “shoot” the DNA into the cell (works best with plants)
Injection of DNA
Inducing the cells by electric or temperature shocking

18. Let the host cell replicate many times
This produces clones
 This is how to make a transgenic organism

19. Plant Plasmids

20. Human Genome Project

21. Human Genome Project
The HGP was an international effort to completely sequence and map the human genome
genome = all of an organism’s genetic material

22. Human Genome Project
The human genome has between 30,000 and 40,000 genes.

23. Human Genome
Chromosome Linkage Maps show the locations of genes on chromosomes  this is just chromosome #1

24. Applications of HGP Genetic testing to diagnose genetic disorders
Developing gene therapy
When normal genes are inserted into cells to correct genetic disorders

25. Gene Therapy
This technique() has been used to treat SCID, sickle-cell anemia, hemophilia
Cystic fibrosis has been treated with cold viruses

26. Applications of HGP DNA Fingerprinting
This is the unique banding pattern created when a sample of DNA is cut and separated
Restriction enzymes cut the DNA
Gel electrophoresis separates the cut pieces by size

27. Gel Electrophoresis
Cut DNA is loaded into a slab of gel (wells are usually at one end)
Electrodes are attached to opposite ends of the gel

28. Gel Electrophoresis, cont.
Negatively charged DNA is pulled towards the positive pole
Small pieces move easily through the gel, thus travelling farther

29. Gel Electrophoresis

30. Uses of DNA Fingerprints
Paternity testing (Who’s the Daddy?)
Forensic analysis to identify suspects and unidentified victims
Classify new organisms/fossils

31. Polymerase Chain Reaction
What if you only have one drop of blood left at a crime scene? How do you test that?
Scientists can make billions of copies of DNA by PCR (polymerase chain reaction)
This simulates DNA replication, but only takes a few hours