Genetic TechnologiesBy: Ting-Yu Tsai

Han Keyl Kim

19.1 Patenting DNA• Biotechnology-Use or alteration of cells or

biological molecules for specific applications.

Organisms that harbor DNA from other species are termed Transgenic and their DNA is called recombinant DNA

The Laboratory, or The Passion of OncoMouse

The OncoMouse or Harvard mouse is a type of laboratory mouse that has been genetically modified using modifications designed by Philip Leder and Timothy A. Stewart of Harvard University to carry a specific gene called an activated oncogene. The activated oncogene significantly increases the mouse’s susceptibility to cancer, and thus makes the mouse suitable for cancer research. The rights to the invention are owned by DuPont. OncoMouse(R) is a registered trademark.

Patented OncoMouse

Key Concept

• Biotechnology is the use of modification of cells or biological molecules for a specific application.

• Patent law regarding DNA has evolved with the technology since the 1970s, and is still changing.

19.2 Amplifying DNA: PCR• Polymerase Chain Reaction (PCR) are the

technologies for amplified DNA that invented by Kary Mullis in 1983. He then won the Nobel prize for PCR in 1993.

• Use of PCR: - DNA cloning for sequencing

- DNA-based phylogeny - Diagnosis of hereditary diseases - Functional analysis of genes - Identification of genetic fingerprints - Detection and diagnosis of infectious diseases

PCR STEPS• Initialization: Heating the

reaction to 94-96°C. It’s only required for DNA polymerases.

• Denaturation: First regular cycling. Heat for separate 2 strands of the target DNA.

• Annealing: 2 short primers and Taq1 DNA polymerase added. Cool to allow primers form hydrogen bond with ends of target sequence.

• Extension: DNA polymerase adds nucleotides to the 3’ end of each primer.

• Final elongation: This step is to ensure that any remaining single-stranded DNA is fully extended.

• Final hold: May be employed for short-term storage of the reaction.

19.3 Modifying DNA• Modifying DNA-Researchers thought about uses and

risks of mixing DNA from different species.

-Recombinant DNA technology was safer than expected, and the technology has spread to industry more swiftly and in more diverse ways.

Cloning vectors

• Plasmid

• Bacteriophage

• Bacterial artificial

• Chromosome (BAC)

• Yeast artificial

• Chromosome (YAC)

Size of insert accepted up to 15

Size of insert accepted up to 15

Size of insert accepted up to 90

Size of insert accepted 100 to 500

• Genomic library: a population of host bacteria, each of which carries a DNA molecule that was inserted into a cloning vector, such that the collection of cloned DNA molecules represents the entire genome of the source organism. This term also represents the collection of all of the vector molecules, each carrying a piece of the chromosomal DNA of the organism, prior to the insertion of these molecules into the host cells.

• DNA probe: a single-stranded DNA molecule used in laboratory experiments to detect the presence of a complementary sequence among a mixture of other singled-stranded DNA molecules.

• cDNA library: is a collection of cloned cDNA (complementary DNA) fragments inserted into a collection of host cells, which together constitute some portion of the transcriptome of the organism. cDNA is produced from fully transcribed mRNA found in the nucleus and therefore contains only the expressed genes of an organism. Similarly, tissue specific cDNA libraries can be produced. In eukaryotic cells the mature mRNA is already spliced, hence the cDNA produced lacks introns and can be readily expressed in a bacterial cell. While information in cDNA libraries is a powerful and useful tool since gene products are easily identified, the libraries lack information about enhancers, introns, and other regulatory elements found in a

genomic DNA library.

Transgenic Plants• Transgenic plants are

easier to create than transgenic animals because plants can be derived from somatic cells.

• Protoplasts: The denude plant cells had their cell walls removed by some manipulations.

Protoplasts

Ti Plasmid

Producing a transgenic plant

• Ti plasmid is a circular plasmid that is a part of the genetic equipments that Agrobacterium tumefaciens use to transduce its genetic material to plants. It normally causes a tumor-like growth.

Bacillus Thuringiensis

• Bt is a soil-dwelling bacterium that commonly used as a pesticide.

• When bt gene is bring into corn cells via a Ti plasmid, the cells regenerate corn plants and produce their own insecticide.

• Possible problems: The pollen form Bt maize could kill the monarch butterfly.

References• http://en.wikipedia.org/wiki/Polymerase_chain_reaction• Chapter 19 Genetic Technologies, Human Genetics 8th Edition, McG

raw-Hill Companies, Ricki Lewis, 2008. • http://www.everythingbio.com/• http://scienceblogs.com/insolence/2007/06/the_autism_omnibus_th

e_difference_betwee.php• http://www.biology.lsu.edu/webfac/nkato/methods/methodImages/Pr

otoplast.jpg• http://www.mun.ca/biology/desmid/brian/BIOL2060/BIOL2060-20/20

32.jpg• http://en.wikipedia.org/wiki/Bacillus_thuringiensis