Cytogenetics I,II; Genetic counseling

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Cytogenetics I,II; Genetic counseling
2012-08-29 19:17:08

med school
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  1. FISH vs. Karotype?
    • FISH: DNA can be interphase or metaphase, can be usedto detect chromosomes less than 3 MB
    • Karotype: DNA has to be in metaphase
  2. Acrocentric; metacentric; submetacentric?
    • acrocentric: centromere causes p/q arms to be unequal
    • metacentric: centromere is at the middle of chromosome
    • submetacentric: centromere is assymetric by close to middle
  3. P vs Q arms?
    • P: petite arm
    • Q: larger arm of chromosome
  4. What do the genes of the p arm on acrocentric DNA code for?
    rRNA genes
  5. What are the acrometric chromosomes?
  6. Processing of banding chromosomes in karotyping?
    Take leukocytes, add mitogen (promotes mitosis), add colcichine, all hypOtonic solution to cause swelling of cells. 
  7. G-banding? R-banding?
    A-T rich areas of chromosome are died dark color. R-banding colors it the opposite way (to verify the chromosome is correctly labeled)
  8. Short clustered repeats of DNA near centrosome?
    Satellite DNA

    **Unique to DNA
  9. Repetitive DNA seqs. dispersed in genome?
  10. Does LINE or Alu code for RT?
  11. How do LINE/Alu cause cancer (i.e. in BRCA --> breast cancer)?
    Get incorporated in genome via retrotransposition
  12. Names, symptoms, and of trisomy 21,18,13?
    • 21: DS, open mouth
    • 18: Edward's, clenched fist and weird feet
    • 13: Patau's, cleft lip, deformity
  13. Types of FISH probing?
    • 1. Whole chromosome
    • 2. Locus Specific - broken down into satellite probes (bind to centromere) and telomere probes (bind to end of chromo.)
  14. Two types of inversion?
    Pericentric: include centromere

    Paracentric: does not include centromere
  15. Two types of deletion (interstitial and terminal)?
    • Interstitial: two strand break
    • Terminal: 1 break in chromosome
  16. Insertion (direct, inverted)?
    Refers to the removal and insertion of a chromosomal segment into DNA (i.e. cut and paste mechanism)
  17. isochromosome?
    when the p-arm of a chromosome is deleted and replaced by duplicate of its q-arm.
  18. When to be non-directive? when to NOT be non-directive?
    non-directive: reproductive situations, appropriateness of genetic testing/aggressive therapy

    directive: the patient will die unless you do this