PCR

1
PCR

• Polymerase Chain Reaction
• Rapid copying of DNA in vitro (in glass)

2
History of PCR

• Kerry B. Mullis awarded the Nobel Prize in
  Chemistry in 1993 for developing PCR in the
  1980s
• Debate about PCR as a concept vs. process
• Mullis claimed the idea of PCR constituted an
  invention.
• an unanticipated solution to a long-standing
  problem
• Stephen Scharf, a colleague of Mullis, said
• that the truly astonishing thing about PCR is
  precisely that it wasn't designed to solve a
  problem once it existed, problems began to
  emerge to which it could be applied.
• Paul Rabinow -- Berkeley, Calif., 1998

3
Kary Mullis

• Conceived of the idea of PCR while driving on
  highway 128 from San Francisco to Mendocino in
  1983
• Independent writer and consultant since 1987
• Avid surfer

4
Original Method

• The original description of the technique was
  little more than a proof of concept, not the
  protocol now carried out by the sleek ranks of
  machines found in many laboratories. This method
  would be monumentally less powerful if it
  required the removal of an incubation tube from a
  water bath every 2 minutes, and the return of the
  tube to a bath of a different temperature.
• Stanley Fields, The interplay of biology and
  technology
• Proc Natl Acad Sci USA. 2001 August 28 98(18)
  1005110054.

5
Original Predictions

• - Saiki R, K. et. al., Enzymatic amplification of
  beta-globin genomic sequences and restriction
  site analysis for diagnosis of sickle cell
  anemia, Science, 1985 Dec 20, 230(4732)1350-4.
• - Mullis K. B et. al., Specific enzymatic
  amplification of DNA in vitro the polymerase
  chain reaction. Cold Spring Harbor Symposia on
  Quantitative Biology, 1986

6
Automated Process

• Thermocyclers are central to biotech labs
• Programmable times and temperatures
• http//www.montreal-biotech.com/Products/ContentIm
  ages/TProfessional20Thermocycler.jpg
• Animation of the method at www.dnalc.org

7
PCR applications
8
PCR use in Medicine

• Diagnostic tests
• Identify determinants of drug resistance
• Monitor the duration and adequacy of therapy
• Provide prognostic information about an illness

9
A Real Life application

• PCR and Tuberculosis
• Tuberculosis can often be hard to give an
  accurate diagnosis as quickly as it is needed to
  start treatment. The common methods of diagnosis
  use acid-fast bacilli (AFB) in tissue samples and
  secretions.
• In a recent study, PCR was used in samples of
  bone marrow to diagnose patients.

10
PCR and tuberculosis cont.

• This test was run by L. Escobedo-Jaimes.
• 30 patients who suspected having tuberculosis
  used the PCR for a diagnosis.
• He found that the PCR method had matched with 70
  of the results from regular diagnosis methods.

11
PCR is also used in

• Environmental Science
• Study and compare organisms reactions to
  global warming
• Agriculture
• Screen processed food such as meats and
  poultry
• Forensics
• Identify potential suspects or prove someone
  innocent of a crime

12
Genetic Counseling
13
What is it?

• Genetic counselors provide patients and families
  with information about a genetic disorder,
  inherited disease, or birth defect they have or
  have the chance of obtaining.
• It is a common prenatal practice to test for any
  possibility of inherited disease.
• They must provide support and serve as educators
  for families and patients.

14
Relationship with patients

• Genetic counseling can be very emotional. How do
  you tell a patient that they have a life altering
  disease?
• To become a genetics counselor not only must you
  have a science background but you must be
  competent in areas such as psychosocial theory,
  ethics and counseling techniques.
• You can develop long-term relationships with
  patients because you track them before testing,
  during testing, and after, and provide medical
  knowledge and emotional support throughout the
  process.

15
Works Cited

• http//archneur.ama-assn.org/cgi/content/full/56/1
  0/1215
• http//www.ajtmh.org/cgi/content/full/75/5/960
• http//www.scied.science.doe.gov/scied/Abstracts20
  05/ORNLenv.htm
• http//www.scied.science.doe.gov/scied/Abstracts20
  05/ORNLenv.htm
• http//www.ornl.gov/sci/techresources/Human_Genome
  /elsi/forensics.shtml
• http//www.genetichealth.com/Resources_What_Is_Gen
  etic_Counseling.shtml
• http//www.salary.com/careers/layouthtmls/crel_dis
  play_Cat10_Ser138_Par238.html