1. DNA Technologies

2. Recombinant DNA methods
Restriction enzymes
Enzymes from bacteria
Used to cut DNA molecules in specific places
Enable researchers to cut DNA into manageable segments
Vector molecule carrier of DNA fragment into cell
Transformation: uptake of foreign DNA into cells

3. Cutting DNA with a restriction enzyme

4. Splicing foreign DNA into a vector
Foreign DNA and plasmid DNA cut with same restriction enzyme
Produces linear molecules with complementary single-stranded ends
Recombinant DNA created by mixing so sticky ends pair
DNA ligase forms covalent bonds, linking the two fragments

5. Plasmids

6. Genomic library Chromosome library cDNA library
Collection of DNA fragments that represent all the DNA in the genome
Chromosome library
All the DNA fragments in that specific chromosome
cDNA library
Produced using reverse transcriptase
Makes DNA copies of mature mRNA

7. Producing a genomic or chromosome library

8. Genetic probes
Segments of single-stranded DNA that can hybridize to complementary base sequences in target gene
Southern blot technique

9. Using a genetic probe to find bacterial cells with a specific recombinant DNA molecule

10. Amplifying DNA in vitro by PCR
Small amount of double-stranded DNA
DNA precursors
Specific nucleic acid primers
Taq DNA polymerase
DNA is denatured
Primers attach to primer-binding site on each DNA strand
Each strand acts as template for DNA synthesis

11. Amplification of DNA by PCR

12. DNA sequencing Based on chain termination method
Yields information about
Structure of gene
Probable amino acid sequences of its encoded proteins

13. Chain termination method of DNA sequencing

14. Applications of DNA technology
Gene therapy
Tissue engineering
DNA typing

15. DNA typing

16. Transgenic organisms
Foreign DNA incorporated into their genetic material
Gene target
Single gene inactivated or “knocked out”
“Knockout mice” used in studying genes
Mutagenesis screening
Male mice treated with mutagens and studied

17. A transgenic mouse
Mouse on right is normal; mouse on left is transgenic
animal expressing
rat growth hormone

18. Transgenic rice
“Golden rice” shown intermixed with white rice contain high concentrations of beta-carotene

19. Safety guidelines Safety concerns Safety measures
Introduction of transgenic organisms into the environment
Health effects on humans from consuming GM crops
Safety measures
Special facilities designed to hold pathogenic organisms
Science of risk assessment