Behavioral Genetics Clicker Questions

In order for Mendel’s monohybrid cross experiment to work, the true breeding plants in the parent generation must be:

Homozygous

Heterozygous

Homozygous (monohybrid= testing one trait and crossing traits)

If both parents are homozygous for the dominant allele the probability that you will display the dominant phenotype is:

0%

25%

50%

100%

100%

If both parents are homozygous for the recessive allele the probability that you will display the dominant phenotype is:

0%

25%

50%

100%

0%

The sour tasting phenotype discovered by accident in 1931.

Gene (TAS2R38) discovered in 2003.

Dominant allele corresponds to the sour tasting phenotype.

Recessive allele (multiple forms) corresponds to the non-tasting phenotype.

In a cross between a true-breeding taster and non-taster

In a cross between a true-breeding taster and heterozygote

In a cross between two heterozygous parents?

Reminder: Taster is the dominant phenotype

What are the possible genotypes of their offspring? Probability of each genotype?

What are the possible phenotypes of their offspring? Probability of each phenotype?

—-

In a cross between a true-breeding taster and non-taster the probability of their offspring showing the tasting phenotype is:

0%

25%

50%

75%

100%

100%

In a cross between a true-breeding taster and heterozygote the probability of the TT genotype is:

0%

25%

50%

75%

100%

50%

In a cross between two heterozygous parents the probability of being a non-taster is:

0%

25%

50%

75%

100%

25%

If you have two of the same alleles (i.e., TT or tt) then you have what type of genetic variant?

Homozygous

Heterozygous

De novo

SNP

Homozygous

If two heterozygous parents produce offspring, the odds that they will produce homozygous offspring are:

0%

25%

50%

100%

50%

Mendel’s law of dominance states that:

Two different alleles will both exert effects on the trait. For example, if an allele for being short and an allele for being tall are present then the trait will be having average height

The dominant allele masks the effect of the recessive allele

The dominant and recessive allele will both exert effects depending on which part of the body the gene is in.

B- the dominant allele masks the effect of the recessive allele

What is the probability of the offspring in this design having yellow skin?

0%

25%

50%

75%

75%

What is the probability of having wrinkly skin?

0%

25%

50%

100%

25%

What is the probability of the offspring having the yyrr genotype (i.e., homozygous for the recessive genotype for both traits)?

1/16

2/16

6/16

12/16

1/16

Conclusion

Dihybrid same results as monohybrid (3-1)

According to Mendel’s second law, if I know what gene you carry for Trait X then I can predict the gene you carry for Trait Y:

True

False

False

All human traits follow a mendelian pattern of inheritance, where a single gene causes the outcome

True

False

False

Mendel used the dihybrid cross design to demonstrate his second law, which states that:

Alleles are inherited randomly

Alleles for one trait are inherited independent of alleles for another trait

One allele can mask or dominate another allele

Dihybrid cross designs work

B: Alleles for one trait are inherited independent of alleles for another trait

Because of 3-1 ratio

In a dihyrbid cross design, the odds of being homozygous recessive for both traits is:

1/2

1/4

1/8

1/16

1/16

For an autosomal recessive disorder to present in the offspring the risk increasing alleles must be present in:

Both parents

Only the paternal side

Only the maternal side

Both parents

1-22 autosomes (same in all individuals)

Both parents because you only get one copy from each parent and you need both

For an X-linked dominant disorder to present in biological male (XY) offspring the dominant allele must be present in:

Both parents

Only the paternal side

Only the maternal side

Only the paternal side (Y chromsome comes from dad)

What is the order of RNA, Protein, and DNA

DNA → RNA → Protein

What are A, T, C, and G

DNA bases

A direct role of genes is to:

Control your heart rate

Provide instructions for making proteins (also known as polypeptides)

Keep our legs warm

Make ribosomes

Provide nstructions for making prteins (also known as polypeptides)

Most of the genome varies across individuals.

True

False

False (.1 percent differnece)

Most of the genome consists of protein coding genes

True

False

False (99% coding, 1% noncoding)

When a gene is expressed, the directional flow of information reflects:

RNA -> DNA -> protein

Protein -> RNA -> DNA

DNA -> RNA -> protein

DNA -> protein -> RNA

DNA → RNA → protein

In a Robertsonian translocation:

One chromosome fuses with another chromosome

Two chromosomes exchange regions

Recombination between two homologous chromosomes occurs

Two sets of chromosomes are deleted

One chromosome fuses with another chromosome

What is recombinations between two homologous chromsomes?

Meiosis

What is it called when two sets of chromsomes are delted?

Doesn’t happen

Karyotyping refers to the process of:

Photographing chromosomes

Aneuploidy

Nondisjunction errors

Trinucleotide repeat expansions

A- photographing chromosomes

Deletion of an entire chromosome is a form of:

Partial trisomy

Aneuploidy

Partial monosomy

A robertsonian translocation

Aneuploidy

What disorder is associated with anepleuidt in chromsome 21

Down syndrome— most common there because 21 is a lot smaller

What disorder is associated with anepleudity in chromsome X

Klinefelters

Organisms that have more chromosomes are more biologically complex

True

False

False

How many autosomal chromosome pairs do humans have?

11

22

23

40

22

23rd chromsome is X and Y chromsome

The primary gene that was being investigated for its association with depression using candidate gene methods was?

DRD2 (dopamine receptor gene)

SCL6A4 (or 5-HTTLPR; serotonin transporter gene)

GABRA1 (GABA receptor gene)

ADH1B (alcohol dehyrdogenase gene)

B

The Common Disease-Common Variant Hypothesis (CDCVH) states:

Common diseases should be caused by genetic variants that are equally common

Common diseases are caused by rare variants with large effect

Common diseases are due to new genetic mutations

Common diseases are caused by aneuploidy

A- Common diseases should be caused by genetic variants that are equally common

Candidate gene studies failed because of:

Uncontrolled population stratification

Low statistical power

Selecting genes that weren’t associated with the phenotype

All of the above

All of the above

Most common genetic variants (MAF > 1%) that are associated with human complex traits have:

Huge effects on the phenotype

Medium effects on the phenotype

Small (very tiny) effects on the phenotype

Small (very tiny) effects on the phenotype

Linkage studies rely on:

The knowledge of where a particular genetic marker for another trait is physically located on the genome

Studying patterns of inheritance within families

The ability to measure the whole genome

A and B

A and B

Candidate gene studies sought to:

Scan the entire genome for genetic effects

Use family-based patterns of inheritance to identify the location of a risk increasing gene

Measure a specific genetic variant based on theory and prior research to see if it is associated with the outcome of interest

Measure a specific genetic variant based on theory and prior research to see if it is associated with the outcome of interest

Candidate gene studies failed to replicate due to:

Small participant sample sizes used to try and detect small effects (i.e., low statistical power)

Failure to control for population stratification

Picking genes that were not actually associated with the traits

All of the above

All of the above

Microarray GWAS studies involve directly measuring (typing):

The entire human genome

The entire human exosome

All common variants (MAF > 1%)

A subset of ~500,000 common variants

A subset

If we find that a genetic variant is associated with a trait, we know that is the causal variant in the population:

True

False

False

Genome-wide studies are currently representative of the different ancestry groups in the global population

True

False

False

The most common plot associated with a genome-wide association study is known as:

Miami Plot

Mahattan plot

Scatter plot

Correlation matrix

Manhattan plot

The x-axis of a manhattan plot are the:

Log10 p-values of the GWAS effects

Chromosomes

centiMorgans

linkage

Chromosomes

The most well-powered GWAS has discovered all of the genetic signal in certian human complex traits

True

False

False

Height: very heritable

GWAS: 40% heritability of height from half a million people

GWAS uses recent technology that only measures most common variants

LD-score regression can be used to estimate

Heritability

Genetic correlations

The effects of individual genetic variants

A and B

A and B

Polygenic scores are most predictive when using:

Only the SNPs (genetic variants) that are significantly associated with the trait

The top 5% of SNPs

The top 50% of SNPs

All SNPs

A

X-chromosome inactivation is a form of

A. GWAS

b. Methyli

C. Epigenetics

D. Cola

Epigenetics

genomic imprinting means

the process by which only one copy of a gene in an individual (either from their mother or their father) is expressed, while the other copy is suppressed.

Functional annotations are constructed using ___ __

GWAS data

Epigenetic reprogramming refers to

How methylation is measured

That sex cells erase 99% of epigenetic signatures

Transcription

C.

Epigenetic research most commonly studies

Methylation

Transcription

Genotypes

Histone Marks

Mythlation

The environmental exposure most often associated with changes in methylation is

Smoking

Exercise

Depression

Alzheimers

Smoking

Measures all genetic varaints

Whole genome sequencing

GWAS examunes the association between a phenotype and

All genetic variants

All common genetic variants

Intronic reigons

Exonic regions

All common genetic variants

If a biological mother is heterozygous for an automsomal dominant disorder, the probability that her offspring will have the disorder are

0%

25%

50%

100%

50%

A researcher selectively breeds mice that are not aggessive at all for 30 generations. She finds that the aggressiveness scores of the two lines of mice do not differ significant;y. Does this result provide evidence for genetic influences on aggression?

Yes

No

No— nondiverging lines means no genetic influence

Two mice differ significantly in senstivity to alcohol. Does this result provide evidence for genetic influences on alcohol sensitivity?

Yes

That same study found that some of the mice were much more sensitivty to alcohol than others. What does this result tell us?

Genetic influences on sensitivity to alcohol

Evviornmental influences on sensitivity to alcohol

No genetic influences on sensitivty to alcohol

No enviornmental influences on sensivitivy to alcohl

Evviornmental influences on sensitivity to alcohol