Using DNA hybridization to Explore Genetic Relationships'

1
Using DNA hybridization to Explore Genetic
Relationships.

• Jason Falconio
• Biology and Anatomy Teacher
• NIH/HHMI Intern

2
Objectives of workshop

• Learn what DNA/DNA hybridization is
• Perform a DNA/DNA hybridization.
• Compare the benefits/limitations of DNA/DNA
  hybridization
• Learn how to teach a lesson on this topic

3
Neisseria gonorrhea

• Gram-negative diplococcus
• One of two of the pathogenic bacteria Neisseria
• Neisseria gonorrhea gonorrhea
• Neisseria meningitidis meningitis and sepsis
• Closely related research often involves both
  species due to the similarities between the
  species

4
Reasons to study gonorrhea

• 361, 705 cases were reported to CDC in 2001-
  second only to chlamydia in terms of sexually
  transmitted diseases. ( CDC, 2001)
• Highest incidence in high density urban areas
  among persons under 24. (CDC, 2001)
• No vaccine currently exists.

5
Reasons to study gonorrhea

• Results in asymptomatic infections especially in
  women. (Turner, 2002)
• Is a major cause of pelvic inflammatory disease,
  salpingitis, and subsequent ectopic pregnancies
  and infertility.
• Infection may lead to sepsis and arthritis

6
Reasons to study por genepor encodes the most
abundant protein found on the outer membrane of
the bacteria.

• The protein is antigenically stable during an
  infection.
• The protein necessary for bacterial survival.
• Viable vaccine candidate.
• Antibodies to Por are bactericidal

7
My research- Molecular epidemiology

• Typed strains of N. gonorrhea from Baltimore from
  1992-1993 to confirm results from a recently
  completed ten year study.
• Helped to redesign probes and controls to improve
  accuracy
• Typed antibiotic resistant strains of N.
  gonorrhea from Israel.

8

• How is DNA/ DNA Hybridization Done?

9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
Benefits of hybridization

• Method is inexpensive and rapid relative to gene
  sequencing
• Can compare targeted sequences of multiple DNA
  samples simply
• Identify the major types of gene sequences found
  in a population of organisms.
• Help to determine the origin of a group of
  organisms.

15
Limitations of DNA/DNA hybridization

• Time consuming relative to some other methods
  used for antigenic characterization of bacteria.
• Most effective on isolated DNA.
• Limited by the probes used.
• Can be labor intensive in the initial stages of
  probe design and preparation.

16
Website extensions

• CDCs main N. gonorrhea website, great fact
  sheets and links
• http//www.cdc.gov/nchstp/dstd/GonorrheaInfo.htm
• http//www.cdc.gov/ncidod/dastlr/gcdir/gono.html
• The NLMs database of journal articles
• www.pubmed.gov

17
Acknowledgments

• Dr. Margaret Bash - FDA.
• Freyja Lynn -FDA.
• Dr. Durrie McKnew -FDA.
• Howard Hughes Medical Institute and the Student
  Teacher Program for the opportunity to work with
  the FDA and NIH

18
Acknowledgments

• Patricia Finecey for her technical assistance-
  SVHS.
• Yvonne Soghomonian for organizing this workshop-
  MCPS.
• Gloria Seelman for helping me plan from the
  beginning- NIH office of Science Ed.

19
References

• Thompson DK, Deal CD, Ison CA, Zenilman JM, Bash
  MC. A typing system for Neisseria gonorrhoeae
  based on biotinylated oligonucleotide probes to
  PIB gene variable regions. J Infect Dis. 2000
  May181(5)1652-60.
• McKnew DL, Lynn F, Zenilman JM, Bash MC. Porin
  variation among clinical isolates of Neisseria
  gonorrhoeae over a 10-year period, as determined
  by por variable region typing. J Infect Dis. 2003
  Apr 15187(8)1213-22.
• Turner CF, Rogers SM, Miller HG, Miller WC,
  Gribble JN, Chromy JR, Leone PA, Cooley PC, Quinn
  TC, Zenilman JM. Untreated gonococcal and
  chlamydial infection in a probability sample of
  adults. JAMA. 2002 Feb 13287(6)726-33. .
• http//www.cdc.gov/nchstp/dstd/GonorrheaInfo.htm
• http//www.cdc.gov/ncidod/dastlr/gcdir/gono.html