MOLECULAR DIAGNOSTICS EXAM #3
QUESTIONS WITH COMPLETE
ANSWERS
STR analysis is performed on bone marrow donor-recipient pairs prior to
transplantation for which of the following reasons? - ANSWER-To find informative
alleles for post-transplantation studies
What is a microvariant? - ANSWER-An STR Allele missing base pairs in the repeat
unit.
What is an expression for how many times morelikely the child's allele is inherited
from the alleged father than by random occurence of the allele in the general
populations? - ANSWER-Paternity index
A woman has been sexually assaulted by an unknown man. Which of the following
laboratory procedures can be used to more accurately analyze residual DNA left by
the man in an effort to identify him? - ANSWER-Y-STR
Which of the following is used as a marker of gender? - ANSWER-Amelogenin
Which of the following polymorphisms are tandem repeats of 1-8 bp? - ANSWER-
Short tandem repeats
How do STR and VNTR differ? - ANSWER-STR have shorter repeat units than
VNTR
STR analysis was performed on a bone marrow donor and recipient pair with the
following results. Which loci are informative?
vWA 12/13, 12/17
THO1 8/11, 8/11
D1sS317 10/14, 9/12
D16S539 9/11, 9/11
F13A01 7/12, 7/12
CSF1PO 13/15, 13/15 - ANSWER-vWA and D13S317
Which are more likely to be successfully analyzed on highly degraded DNA? -
ANSWER-Mini-STR
DNA found at the scene of the crime determined to have one peak at 212 bp at the
amelogenin locus. The source of this DNA is which of the following? - ANSWER-
Female
An individual who has two populations of cells that were derived from two different
zygotes is called a: - ANSWER-Chimera
, HIV genotyping is performed for which of the following reasons? - ANSWER-Monitor
development of antiretroviral drug resistance
Which of the following genes is the target in molecular-based assays that are used to
quantify the amount of HIV in a patient? - ANSWER-gag
When a typing method is repeated and the results are the same each time, the
method has high: - ANSWER-Reproducibility
Which of the following genes is a target in molecular-based assays and confers
resistance to vancomycin in the enterococci? - ANSWER-vanA
In a PCR assay of DNA isolated from a nasopharyngeal swab, amplification using
primers to IS481 was positive and using primers to IS1001 was negative. All controls
were acceptable. Which of the following organisms was present in this sample? -
ANSWER-Bordella pertussis
PCR with RFLP analysis and reverse hybridization is the principle of which of the
following commercial assays? - ANSWER-Inno-LIPA
A PCR assay using primers specific for the autolysin gene (lytA) was performed on a
sputum specimen from a 10 year old girl. The specimen was positive, and all
controls were acceptable. Which of the following is the best interpretation of these
results? - ANSWER-Streptococcus pneumoniae is present, but clinical significance is
questionable.
What characteristic of parasites complicates molecular testing? - ANSWER-
Resistance to disruption and lysis
Which of the following molecular-based assays target rRNA? - ANSWER-Accuprobe
for M. tuberculosis
Which virus does not share sequence homology with the others? - ANSWER-HCV
A positive control is added into a test specimen. The test results of the specimen
alone and the spiked mixture are negative. What does this most likely indicate? -
ANSWER-The specimen contains an inhibitor
Which of the following typing methods is an RNA test? - ANSWER-Ribotyping
DNA is isolated from a test organism and cut with restriction enzymes. The
fragments are ligated to adapters that are complementary to primers that are added
to perform two rounds of PCR. The PCR products are separated by gel
electrophoresis and analyzed. Which of the following methods was described? -
ANSWER-Amplified fragment length polymorphism
Which of the following is the molecular target for most epidemiological investigations
of Mycobacterium tuberculosis? - ANSWER-IS6110
QUESTIONS WITH COMPLETE
ANSWERS
STR analysis is performed on bone marrow donor-recipient pairs prior to
transplantation for which of the following reasons? - ANSWER-To find informative
alleles for post-transplantation studies
What is a microvariant? - ANSWER-An STR Allele missing base pairs in the repeat
unit.
What is an expression for how many times morelikely the child's allele is inherited
from the alleged father than by random occurence of the allele in the general
populations? - ANSWER-Paternity index
A woman has been sexually assaulted by an unknown man. Which of the following
laboratory procedures can be used to more accurately analyze residual DNA left by
the man in an effort to identify him? - ANSWER-Y-STR
Which of the following is used as a marker of gender? - ANSWER-Amelogenin
Which of the following polymorphisms are tandem repeats of 1-8 bp? - ANSWER-
Short tandem repeats
How do STR and VNTR differ? - ANSWER-STR have shorter repeat units than
VNTR
STR analysis was performed on a bone marrow donor and recipient pair with the
following results. Which loci are informative?
vWA 12/13, 12/17
THO1 8/11, 8/11
D1sS317 10/14, 9/12
D16S539 9/11, 9/11
F13A01 7/12, 7/12
CSF1PO 13/15, 13/15 - ANSWER-vWA and D13S317
Which are more likely to be successfully analyzed on highly degraded DNA? -
ANSWER-Mini-STR
DNA found at the scene of the crime determined to have one peak at 212 bp at the
amelogenin locus. The source of this DNA is which of the following? - ANSWER-
Female
An individual who has two populations of cells that were derived from two different
zygotes is called a: - ANSWER-Chimera
, HIV genotyping is performed for which of the following reasons? - ANSWER-Monitor
development of antiretroviral drug resistance
Which of the following genes is the target in molecular-based assays that are used to
quantify the amount of HIV in a patient? - ANSWER-gag
When a typing method is repeated and the results are the same each time, the
method has high: - ANSWER-Reproducibility
Which of the following genes is a target in molecular-based assays and confers
resistance to vancomycin in the enterococci? - ANSWER-vanA
In a PCR assay of DNA isolated from a nasopharyngeal swab, amplification using
primers to IS481 was positive and using primers to IS1001 was negative. All controls
were acceptable. Which of the following organisms was present in this sample? -
ANSWER-Bordella pertussis
PCR with RFLP analysis and reverse hybridization is the principle of which of the
following commercial assays? - ANSWER-Inno-LIPA
A PCR assay using primers specific for the autolysin gene (lytA) was performed on a
sputum specimen from a 10 year old girl. The specimen was positive, and all
controls were acceptable. Which of the following is the best interpretation of these
results? - ANSWER-Streptococcus pneumoniae is present, but clinical significance is
questionable.
What characteristic of parasites complicates molecular testing? - ANSWER-
Resistance to disruption and lysis
Which of the following molecular-based assays target rRNA? - ANSWER-Accuprobe
for M. tuberculosis
Which virus does not share sequence homology with the others? - ANSWER-HCV
A positive control is added into a test specimen. The test results of the specimen
alone and the spiked mixture are negative. What does this most likely indicate? -
ANSWER-The specimen contains an inhibitor
Which of the following typing methods is an RNA test? - ANSWER-Ribotyping
DNA is isolated from a test organism and cut with restriction enzymes. The
fragments are ligated to adapters that are complementary to primers that are added
to perform two rounds of PCR. The PCR products are separated by gel
electrophoresis and analyzed. Which of the following methods was described? -
ANSWER-Amplified fragment length polymorphism
Which of the following is the molecular target for most epidemiological investigations
of Mycobacterium tuberculosis? - ANSWER-IS6110
