1. Cutting and Pasting DNA The cutters are called restriction enzymes, they cut DNA at specific nucleotide sequences

2. Restriction enzyme cuts DNA into fragments 1 2 3 4 Addition of a DNA fragment from another source Fragments stick together by base pairing DNA ligase joins the strands Recognition sequence for a restriction enzyme Sticky end Recombinant DNA molecule

3. How Do I Obtain the Gene of Interest? The “shotgun” approach - millions of recombinant plasmids are produced; a genomic library

4. How a DNA probe tags a gene Radioactive probe (DNA) Single-stranded DNA Mix with single-stranded DNA from various bacterial clones Base pairing indicates the gene of interest

5. The reverse transcriptase method Transcription 1 2 3 4 Introns removed and exons spliced together Isolation of mRNA from cell and addition of reverse transcriptase 5 Synthesis of second DNA strand Synthesis of cDNA strand ExonIntronExonIntronExon Cell nucleus DNA of eukaryotic gene RNA transcript mRNA Cytoplasm Reverse transcriptase Test tube cDNA strand being synthesized cDNA of gene with- out introns

6. DNA technology revolutionized forensics WHO ARE YOU? –forensics is the scientific analysis of evidence from crime scene investigations

7. DNA fingerprinting has been available since 1986DNA fingerprinting Used in CSI, victim IDs; Cheddar Man Crimes and Other Investigations

8. Polymerase Chain Reaction (PCR) copies DNA DNA Fingerprinting Techniques - PCR

9. DNA amplification by PCR Tiny amount of DNA 8421 Number of DNA molecules

10. DNA fragments cut by restriction enzymes are seen as “bands” in an electrophoresis gel Longer fragments Shorter fragments Crime scene DNA Suspect DNA

11. Defendant’s blood Blood on defendant’s clothes Victim’s blood

12. The science of studying entire genomes GENOMICS

13. In 1990, an international consortium began the Human Genome Project The Human Genome Project –sequencing the human genomesequencing –challenges: large size, and the fact that only a small amount of our DNA is genetic

14. Genome mapping Chop up with restriction enzyme Chromosome Sequence fragments DNA fragments Align fragments Reassemble full sequence

15. Gene therapy cures disease by altering human genes HUMAN GENE THERAPY

16. Normal human gene isolated and cloned 1 2 3 Human gene inserted into virus Virus injected into patient Healthy individual Nonharmful virus (vector) Virus containing normal human gene Bone marrow

17. Great power brings both promise and danger SAFETY AND ETHICAL ISSUES –strict laboratory safety procedures are used –negotiators from 130 countries agreed on a Biosafety Protocol for GM foods