18. Molecular Genetic Tools

Methods for Analyzing DNA

Open Question
The results shown are from a DNA test for four genes used in a paternity identification case. DNA for the mother (M) and her child (C) are shown along with DNA from two possible fathers, F1 and F2.Based on the exclusion principle, is either man excluded as the possible father? Explain.
Open Question
The results shown are from a DNA test for four genes used in a paternity identification case. DNA for the mother (M) and her child (C) are shown along with DNA from two possible fathers, F1 and F2.In the 'C' column, label the DNA bands contributed by the mother with 'M' and the DNA bands contributed by the father with 'F.'
Open Question
As genetic testing becomes widespread, medical records will contain the results of such testing. Who should have access to this information? Should employers, potential employers, or insurance companies be allowed to have this information? Would you favor or oppose having the government establish and maintain a central database containing the results of individuals' genome scans?
Open Question
Figure E.1 illustrates the results of an electrophoretic analysis of 13 CODIS STR markers on a DNA sample and identifies the alleles for each gene. Table E.2 lists the frequencies for alleles of three of the STRs shown in the figure. Use this information to calculate the frequency of the genotype for STR genes FGA, vWA, and D3S1358 given in Figure E.1.
Open Question
Might it make sense someday to sequence every newborn's genome at the time of birth? What are the potential advantages and concerns of this approach?
Open Question
Additional STR allele frequency information can be added to improve the analysis in Problem 8. The frequency of D8S1179₁₂ = 0.12. The frequency of D16S539₁₈ = 0.08 and of D16S539₂₀ = 0.21. Lastly, D18S51₁₉ = 0.13 and D18S51₂₀ = 0.10. Combine the allele frequency information for these three STR genes with the information used in Problem 8 to calculate the frequency of the genotype for six of the STR genes.
Open Question
Which of the examples of genetic testing below are prognostic tests? Which are diagnostic?

DNA sequencing of a breast tumor reveals mutations in the BRCA1 gene.
Open Question
Which of the examples of genetic testing below are prognostic tests? Which are diagnostic?

ASO testing determines that an individual is a carrier for the mutant β-globin allele (βˢ) found in sickle-cell anemia.
Open Question
Which of the examples of genetic testing below are prognostic tests? Which are diagnostic?

Individual sequencing (personal genomics) identifies a mutation associated with Alzheimer's disease.
Open Question
Which of the examples of genetic testing below are prognostic tests? Which are diagnostic?

An adult diagnosed with Asperger syndrome (AS) has a genetic test that reveals a SNP in the GABRB3 gene that is significantly more common in people with AS than the general population.
Open Question
Which of the examples of genetic testing below are prognostic tests? Which are diagnostic?

Genetic testing in a healthy teenager identifies an SNP correlated with autism.
Open Question
The frequencies of the four alleles contributed to the child by possible father F1 in Problem 7 are 0.18, 0.23, 0.13, and 0.14.Make a statement about the possible paternity of F1 based on this analysis.
Open Question
The frequencies of the four alleles contributed to the child by possible father F1 in Problem 7 are 0.18, 0.23, 0.13, and 0.14.Calculate the Combined Paternity Index (CPI) for the four genes in this analysis.
Open Question
Does genetic analysis by ASO testing allow for detection of epigenetic changes that may contribute to a genetic disorder? Explain your answer.
Open Question
In an inheritance case, a man has died leaving his estate to be divided equally between 'his wife and his offspring.' His wife (M) has an adult daughter (D), and they argue that they should split the estate equally. As a young couple, however, the man and his wife had a son that they gave up for adoption. Two men have appeared, each claiming to be the son of the couple and therefore entitled to a one-third share of the estate. The accompanying illustration shows the results of DNA analysis for five genes for the mother (M), her daughter (D), and the two claimants (S1 and S2).How many nonmaternal DNA bands are shared by D and S1? By D and S2?