Deck 10: Human Genetic Mapping, Genome Wide Association Studies, and Complex Traits

Question 1

What molecular genetics term is used for making a connection between the gene as it relates to a phenotype and the gene in terms of its DNA sequence?

A) Linkage
B) Mapping
C) Genome-wide association
D) Positional cloning

Answer 1

Positional cloning

Question 2

The On-line Mendelian Inheritance in Man (OMIM) database is an important resource for human genetics. Most of the content in OMIM relates to monogenic diseases. Which of the following conditions are not generally thought to be monogenic? Please select all that apply.

A) Hypertension
B) Cystic fibrosis
C) Type 2 diabetes
D) Huntington disease

Answer 2

Hypertension
Type 2 diabetes

Question 3

Genetic analysis in model organisms such as Drosophila cannot easily be replicated in humans. Which of the following factors are true of Drosophila but not humans? Please select all that apply.

A) Short generation times
B) Crossovers between homologous chromosomes
C) Large numbers of offspring
D) Haploid gametes

Answer 3

Short generation times
Large numbers of offspring

Question 4

Match the missing words in the following phrase. In [A]-Wide Association Studies, researchers identify lots of [B] with ([C]) and without ([D]) a [E]. Genomes are compared and any [F] that are consistently associated with the trait are identified.

Question 5

What does linkage disequilibrium refer to?

A) Genes on different chromosomes
B) Genes on the same chromosome
C) Association of phenotypes
D) Sex-linked phenotypes

Question 6

Match the type of DNA sequence variation with its name

-Changes in the number of copies of a small sequence

A) CNV
B) SNP
C) Private polymorphism
D) Indel

Question 7

Match the type of DNA sequence variation with its name

-Changes at one nucleotide

A) CNV
B) SNP
C) Private polymorphism
D) Indel

Question 8

Match the type of DNA sequence variation with its name

-Changes occurring only in a small number of related individuals

A) CNV
B) SNP
C) Private polymorphism
D) Indel

Question 9

Match the type of DNA sequence variation with its name

-Additions or deletions of pieces of DNA

A) CNV
B) SNP
C) Private polymorphism
D) Indel

Question 10

For a locus to be classed as polymorphic, the second most common polymorphism must be found at least 10% of the time.

Question 11

Why are regions between genes (intergenic regions) often chosen as mapping markers in genome-wide association studies? Please select all that apply.

A) Intergenic regions are usually not under positive or negative selection
B) Polymorphism frequency in intergenic regions is usually unaffected by the health of the individuals
C) Intergenic regions are less likely to contain crossovers during meiosis
D) Variation in intergenic regions is more strongly linked to ethnicity than is variation in genic regions

Question 12

Consider two genes, A and B, with alleles A & a, and B & b. In a population, 60% of gametes have A and 40% have a; 90% of gametes have B and 10% have b. In an experiment, 625 gametes are AB, 408 are aB, 72 are Ab, and 45 ab. Which of the following statements are true about genes A and B in this population? Please select all that apply.

A) Linkage disequilibrium is present
B) Linkage disequilibrium is not present
C) Alleles A and B are linked
D) Alleles A and B are not linked

Question 13

Exome sequencing is powerful technique that has been used to identify genes linked to a number of rare genetic conditions. Which of the following is a disadvantage of exome sequencing?

A) Exome sequencing only identifies conditions associated with recessive alleles.
B) Exome sequencing does not directly identify the gene, but identifies only the region of the genome containing the gene.
C) Exome sequences are more difficult to analyze than whole genome sequences
D) Exome sequencing does not identify conditions linked to regulatory regions.

Question 14

Microarrays can be used to examine gene expression and also to conduct genome-wide association studies (GWAS). Which of the following are true about these microarrays? Please select all that apply.

A) Both expression microarrays and GWAS arrays are hybridized with genomic DNA
B) Both expression microarrays and GWAS arrays are made of printed DNA features
C) Expression microarrays contain features from genes, GWAS arrays contain features from the whole genome
D) Both expression microarrays and GWAS arrays are made of printed RNA features

Question 15

Nine features of a GWAS array are shown, as well as the hybridization results from an experiment (hybridized = red, not hybridized = white). What is the genotype of the person being investigated?
$\begin{array} { | l | l | l | } \hline \text {..GCTAGTCCG.. } & \text {..AAATATCAGT.. } & \text {..CCTGGGCTAG.. } \\\hline \text {..GCTACTCCG.. } & \text {..AAATTTCAGT.. } & \text {..CCTGGCCTAG.. } \\\hline \text {..GCTAATCCG.. } & \text {..CCTGGACTAG.. } & \text {..CCTGGTCTAG.. } \\\hline\end{array}$

A) G/A, T/C, T/T
B) G/G, T/T, G/G
C) A/C, A/A, G/A
D) G/G, A/T, C/T

Question 16

What term is used for a block of alleles that is inherited together?

A) Genome
B) Marker
C) Polymorphism
D) Haplotype

Question 17

Which if the following statements about human evolution and diversity is true?

A) Humans first evolved in the Middle East
B) Human populations are a subset of the genetic diversity found in the Middle East
C) Most of the genetic diversity in humans is found outside of Africa
D) Genetic diversity is greater in Africa than in other regions of the world

Question 18

Fill in the blank. Migrating humans often lived in small groups, and by chance the genetic diversity in these groups may have been different to the diversity in the wider population. This phenomenon is known as the ____ ___

Question 19

Cystic fibrosis (CF) is a common disease in European populations. Most individuals with the disease have the same mutation in the CF gene. What does this suggest about the evolution of CF?

A) The CF mutation first arose in Africa
B) The CF mutation is more common in homozygotes than in heterozygotes
C) Carriers of the European CF mutation are descended from the same person
D) There is a common variant for CF

Question 20

People with a genetic disease that is common in one population but uncommon in other populations usually have the same haplotype.

Question 21

Which of the following pieces of evidence suggest that genetic factors have an influence on height? Please select all that apply.

A) Japanese Americans tend to be shorter than Swedish Americans
B) Adopted children are closer in height to their birth parents than their adopted parents
C) Identical twins are not always the same height
D) Sibling heights are often more similar to each other than to heights of others in the same environment.

Question 22

What term is used for genes that affect the phenotype of a complex trait?

A) Polymorphic genes
B) Polygenic traits
C) Multifactorial traits
D) Quantitative trait loci

Question 23

Match the missing words in the following phrase. Analysis of complex traits requires [A] analysis to determine how much of the [B] in a trait is attributable to genetics. When measurements are taken of a [C] in a population, e. g., height, the results form a [D]. Many of these follow [E] shapes but this is not always the case - for example, flies with red or white eyes fall into two [F] categories.

Question 24

Complex traits are affected by multiple genes. Individuals with the same phenotype for a complex trait will also share the same genotype.

Question 25

Fill in the blank. If all individuals in a population carry the same allele for a particular gene, then the allele is said to be ____ in that population

Question 26

Which of the following can a genome-wide association study not do?

A) Identify different haplotypes in different populations
B) Identify haplotypes associated with a trait
C) Identify multiple regions of the genome that influence a trait
D) Identify causative genes underlying a trait

Question 27

What term is used for the fraction of phenotypic variation that can be attributed to genetic differences among individuals?

A) quantitative traits
B) variance
C) mean
D) heritability

Question 28

What does a Manhattan plot show?

A) The inheritance pattern of a particular trait.
B) Associations of phenotypes with locations on the chromosomes
C) The genes associated with a particular trait
D) The distribution of phenotypes in a population