Question 1

Which of the following best describes the main advantage of genome-wide association studies (GWAS) in mapping human disease genes?

Accepted Answer

GWAS can map susceptibility to many loci for polygenic diseases, each contributing a small effect.

Question 2

A SNP chip is used to analyze a person's DNA. What is the principle behind how a SNP chip detects specific alleles?

Accepted Answer

SNP chips rely on the hybridization of labeled DNA fragments to allele-specific probes, with fluorescence indicating a match.

Question 3

Which equation would you use to calculate the probability of a random match between a suspect and a crime scene DNA sample using STR loci?

Accepted Answer

Multiply the frequencies of each matching genotype across all loci: $$P = f_1$ 	imes f_2$ 	imes ... 	imes f_n$$

Question 4

Which of the following is a real-world application of pharmacogenomics?

Accepted Answer

Identifying SNPs that predict a patient's response to codeine based on CYP2D6 gene variants.

Question 5

Why is Taq DNA polymerase used in PCR instead of E. coli DNA polymerase?

Accepted Answer

Taq DNA polymerase is thermostable and can withstand the high temperatures needed for DNA denaturation ($$95^\circ C).$$

Question 6

A child inherits a mitochondrial disease. Which inheritance pattern does this suggest?

Accepted Answer

Maternal (uniparental) inheritance

Question 7

Which of the following statements about STRs (Simple Tandem Repeats) is correct?

Accepted Answer

STRs are highly polymorphic and are used in forensic DNA profiling.

Question 8

In a PCR reaction, what is the correct order of temperature steps in each cycle?

Accepted Answer

Denaturation ($$95^\circ C$$), primer annealing ($$50-60^\circ C$$), extension ($$72^\circ C)$$

Question 9

Which of the following best explains why mitochondrial DNA is useful for tracing maternal ancestry?

Accepted Answer

Mitochondrial DNA is inherited only from the mother and does not undergo recombination.

Question 10

A person is heterozygous at an STR locus. What would you expect to see on a gel after PCR amplification of this locus?

Accepted Answer

Two bands, each corresponding to a different allele.

Question 11

Which of the following is NOT a potential use of personal genetic information?

Accepted Answer

Predicting exact future phenotypes with 100% certainty

Question 12

Which of the following best describes a polygenic risk score?

Accepted Answer

A statistical estimate of disease risk based on the combination of multiple SNPs across the genome.

Question 13

Why is the probability of a random match between two unrelated individuals at 20 STR loci so low?

Accepted Answer

Because the probability is calculated by multiplying the genotype frequencies at each independent locus, resulting in a very small number.

Question 14

Which of the following statements about the 'Out-of-Africa' hypothesis is supported by mitochondrial DNA analysis?

Accepted Answer

There is more mitochondrial DNA diversity in Africa than in the rest of the world.

Question 15

Which of the following is true about the inheritance of the Y chromosome?

Accepted Answer

It is inherited only from the father and does not recombine with the X chromosome.

Question 16

A forensic scientist is analyzing a crime scene sample using PCR and STR markers. What is the main reason for using multiple STR loci?

Accepted Answer

To decrease the probability of a random match and increase the power of discrimination.

Question 17

Which of the following best explains why direct-to-consumer genetic testing services may not always provide actionable health advice?

Accepted Answer

Most doctors are not trained to interpret complex genetic test results.

Question 18

Which of the following is a correct statement about the use of mitochondrial and Y chromosome DNA in tracing human ancestry?

Accepted Answer

Mitochondrial DNA traces maternal lineage, while Y chromosome DNA traces paternal lineage.

Question 19

Which of the following is a limitation of GWAS in identifying disease-causing variants?

Accepted Answer

GWAS can only identify SNPs that are statistically associated with disease, not necessarily causal.

Human Genome and Human Genetic Variation: Applications in Medicine, Forensics, and Evolution

Study Guide - Practice Questions