MOLECULAR DIAGNOSTICS EXAM
SET QUESTIONS AND ANSWERS
What are some of the limitations of molecular genetic testing? - ANSWER-Most
therapeutic targets are phenotype (don't need to know genotype to treat phenotype),
Mutations may not predict phenotype (have mutation but not have disease state)
Genetic mutation in the absence of symptoms
Explain the concept of penetrance - ANSWER-Frequency gene is expressed, can be
incomplete (people have mutation but don't have phenotype)
Describe the different types of polymorphic DNA sequences (RFLP, VNTR, STR,
SNP) - ANSWER-RFLP-restriction fragment length polymorphism VNTR- variable
number tandem repeats (8 to under 50 bp) STR- short tandem repeat (1-8 bases)
SNP-single nucleotide polymorphisms (one mismatch)
Name some of the challenges associated with forensic DNA testing - ANSWER-
Degraded DNA samples Mixed DNA samples (multiple people in sample) Inhibitors
to PCR present in sample
Explain how restriction fragment length polymorphisms are inherited - ANSWER-for
each locus one allele is inherited from each parent
Describe the method used for STR analysis - ANSWER-Multiplex PCR-looking at
small tandem repeat areas and multiple LOCI. How big are STR in individual
Explain what CODIS is - ANSWER-Combined DNA index system- FBI data of DNA
profiles. Looks for STR markers. 20 different loci to make a match between persons
profile and DNA evidence
What is the amelogenin locus and what is it used for? - ANSWER-not an STR but on
XY chromosomes. 1 band=female 2 bands=male
What is Y STR analysis and when might it be used? - ANSWER-No recombination of
Y chromosome- males in same family have same haplotype Low mutation rate Not
as discriminatory as regular STR analysis
Describe the difference between oncogenes and tumor suppressor genes -
ANSWER-Pre disposed to cancer onco-promote cell divison and survival (dominant)
Tumor suppressor-stop cells from dividing so loss of function (recessive)
What are BRCA1 and BRCA2? - ANSWER-Breast cancer and ovarian cancer 1 on
chromosome 17 2 on chromosome 12
What are the differences between heritable cancer and sporadic cancer? -
ANSWER-Heritable will happen earlier in life; overall increased risk in developing
cancer than the general population; higher risk for second or third diagnosis.
Sporadic happen randomly
SET QUESTIONS AND ANSWERS
What are some of the limitations of molecular genetic testing? - ANSWER-Most
therapeutic targets are phenotype (don't need to know genotype to treat phenotype),
Mutations may not predict phenotype (have mutation but not have disease state)
Genetic mutation in the absence of symptoms
Explain the concept of penetrance - ANSWER-Frequency gene is expressed, can be
incomplete (people have mutation but don't have phenotype)
Describe the different types of polymorphic DNA sequences (RFLP, VNTR, STR,
SNP) - ANSWER-RFLP-restriction fragment length polymorphism VNTR- variable
number tandem repeats (8 to under 50 bp) STR- short tandem repeat (1-8 bases)
SNP-single nucleotide polymorphisms (one mismatch)
Name some of the challenges associated with forensic DNA testing - ANSWER-
Degraded DNA samples Mixed DNA samples (multiple people in sample) Inhibitors
to PCR present in sample
Explain how restriction fragment length polymorphisms are inherited - ANSWER-for
each locus one allele is inherited from each parent
Describe the method used for STR analysis - ANSWER-Multiplex PCR-looking at
small tandem repeat areas and multiple LOCI. How big are STR in individual
Explain what CODIS is - ANSWER-Combined DNA index system- FBI data of DNA
profiles. Looks for STR markers. 20 different loci to make a match between persons
profile and DNA evidence
What is the amelogenin locus and what is it used for? - ANSWER-not an STR but on
XY chromosomes. 1 band=female 2 bands=male
What is Y STR analysis and when might it be used? - ANSWER-No recombination of
Y chromosome- males in same family have same haplotype Low mutation rate Not
as discriminatory as regular STR analysis
Describe the difference between oncogenes and tumor suppressor genes -
ANSWER-Pre disposed to cancer onco-promote cell divison and survival (dominant)
Tumor suppressor-stop cells from dividing so loss of function (recessive)
What are BRCA1 and BRCA2? - ANSWER-Breast cancer and ovarian cancer 1 on
chromosome 17 2 on chromosome 12
What are the differences between heritable cancer and sporadic cancer? -
ANSWER-Heritable will happen earlier in life; overall increased risk in developing
cancer than the general population; higher risk for second or third diagnosis.
Sporadic happen randomly
