Genetics Exam 2 Alam

If a cell is fused with another cell, which of the following would be the best example of a trans-mechanism of epigenetic control? a. a gene that is originally silenced in one cell but expressed in the other is silenced in the hybrid b. a gene that is originally silenced in one cell but expressed in the other is still expressed in the hybrid c. the methylation pattern of the same gene from either cell is not altered d. there are no examples that could conform to a trans-mechanism

A. A gene that is originally silenced in one cell but expressed in the other is silenced in the hybrid

Studies of X-linked inheritance and sex chromosomes provided the evidence for which of the following? a. Chromosomal theory of inheritance b. Particulate theory of inheritance c. Theory of natural selection d. Law of segregation e. Principle of dominance

A. Chromosomal theory of inheritance

In cancer cells one allele of the tumor suppressor gene p53 is frequently mutated so that the protein is inactive, not produced, or deleted. The other allele will usually have a normal sequence and the promoter remains intact but the gene is not expressed. Sequencing with sodium bisulfite modification of DNA can be used to detect which cytosines are methylated. If the cancer cell DNA is sequenced what would be the anticipated results? a. cytosines in or near the promoter region will be methylated b. cytosines in or near the promoter will not be methylated c. cytosines in the coding region will have an increased methylation d. there will be no differences in the methylation pattern of the promoter of p53 from a cancer cell and a normal cell

A. Cytosines in or near the promoter region will be methylated

A symbiotic relationship where one organism lives inside another species is called _____________. a. endosymbiosis b. genomic imprinting c. cytoplasmic inheritance d. heteroplasmy e. exosymbiosis

A. Endosymbiosis

Which of the following is an example of epigenetic inheritance: a. expression of the Lgf-2 gene based on methylation of the ICR and DMR regions b. inheritance of flower color as studied by Mendel c. leaf coloration based on mitochondrial inheritance d. snail shell twist patterns

A. Expression of the Lgf-2 gene based on methylation of the ICR and DMR regions

The inheritance patterns of genetic material is NOT contained in the nucleus of the cell is called ___________. a. extranuclear inheritance b. imprinting inheritance c. maternal effect d. All of these above

A. Extranuclear inheritance

These individuals determined that DNA was responsible for the process of transduction in T2 phage a. Hershey and Chase b. Avery, Macleod, and McCarthy c. Watson and Crick d. Creighton and McClintock

A. Hershey and Chase

A mutation in Xist which prevents binding that promote compaction would interfere with which stage of X inactivation? a. Initiation b. Spreading c. Maintenance d. None of the above

A. Initiation

In a given mapping experiment, you expect that incidence of double crossovers is 3.5%, but you only observe 2.5%. This can be explained by _______________. a. interference b. linkage c. coincidence d. segregation

A. Interference

Which of the following statements about a lethal allele is NOT correct? a. lethals alleles are always recessive b. lethal allelels may have a late age of onset c. lethal alleles may be caused by mutations in essential genes d. lethal alleles may affect one individual differently than another

A. Lethal alleles are always recessive

In a Z-W system, which is considered to be the homogametic sex? a. Males b. Females

A. Males

mtDNA stands for ________ and cpDNA stands for ________. a. mitochondrial DNA; chloroplast DNA b. mutated DNA; complete DNA c. chloroplast DNA; mitochondrial DNA d. methylated DNA; compacted DNA e. none of the above

A. Mitochondrial DNA; chloroplast DNA

In a mapping experiment with three genes, which phenotype should occur most often in the F2 offspring? a. parental phenotypes b. phenotype of individuals with single crossover events c. phenotypes of individuals with double crossover events d. all of these choices should be equal in the F2 generation

A. Parental phenotypes

In the Igf-2 allele, which chromosome is imprinted? Which is expressed? a. paternal, paternal b. paternal, maternal c. maternal, paternal d. maternal, maternal

A. Paternal, paternal

Gene methylation can be detected through the use of restriction endonucleases. Usually these are used in pairs where one enzyme will digest only unmethylated DNA in its recognition sequence while the other is insensitive to methylation. Which of the following is correct? a. the enzyme that is insensitive to methylation serves as a control to make sure the inability of the other enzyme to digest DNA is not due to a mutation b. these are used in pairs since experiments have to be replicated and this one way of preforming a replication of the experiment c. the experimental design is flawed since there should be a third enzyme that would serve as a positive control d. this experimental design is able to detect most of the methylated C residues in a particular region of DNA

A. The enzyme that is insensitive to methylation serves as a control to make sure the inability of the other enzyme to digest DNA is not due to a mutation

Following crossing-over, chromosomes with genetic combinations that resemble the parents are called nonrecombinant a. true b. false

A. True

The best way to identify an X-linked trait in fruit flies is that the trait affects one sex more often than the other. A. True B. False

A. True

The locus is the physical place of a gene on a chromosome a. true b. false

A. True

The process of recombination may rarely occur during mitosis a. true b. false

A. True

A man with A blood type married with a lady who is AB blood type. What blood type is NOT possible in their kids? a. Type O Blood b. Type A Blood c. Type B Blood d. Type AB Blood

A. Type O Blood

The Lyon hypothesis attempts to explain the molecular mechanism of ____________. a. X-inactivation b. genomic imprinting c. maternal inheritance d. extra nuclear inheritance

A. X-inactivation

If a human cell has teo Barr bodies then the genotype of the individual could be a. XXXY b. XXXXY c. XXY d. XYY

A. XXXY

What genes appear to be controlled by the Xic? a. Xist and Tsix b. Xist c. TsiX d. Xic

A. Xist and Tsix

Holandric genes are found on ___________. a. Y-chromosomes only b. X-chromosomes only c. autosomes d. all of the above

A. Y-chromosomes only

Dosage compensation offsets the problems associated with differences in the number of ________ chromosomes in many species. A. sex b. autosome c. somatic d. nuclear

A. sex

Brown spotting of the teeth in humans is caused by a dominant X-linked gene. If a man with normal teeth marries a woman with brown teeth who has a father with normal teeth, then _________________ of their daughters will have brown teeth. a. 100% b. 50% c. 25% d. 0%

B. 50%

You begin to study a novel plant species and discover that this diploid plant has 16 chromosomes. How many linkage groups would you expect to find? a. 16 b. 8 c. 4 d. it is impossible to tell from the information

B. 8

The individuals who determined that Griffith's transforming principle was DNA were a. Hershey and Chase b. Avery, Macleod, and McCarty c. Watson and Crick d. Creighton and McClintock

B. Avery, Macleod, and Mccarty

Which of the following is part of the process of X chromosome inactivation: a. expression of Xist from both chromosomes at the start of the process b. binding of multiple Xist transcripts to Xic on the X chromosome that will be inactivated c. compaction of the active X chromosome into a Barr body d. binding of Tsix transcripts to the X chromosome to be inactivated after the Xist transcripts binds to Xic

B. Binding of multiple Xist transcripts to Xic on the X chromosome that will be inactivated

Which of the following does not inactivate an X chromsome? a. mammals b. drosophila c. c. elegans d. humans

B. Drosophila

Which of the following statements is correct? a. changes in gene expression based on environmental conditions are not considered normal while developmental changes are b. environmental epigenetic changes can vary due to the exposure of the organism to different environmental conditions, while those programmed during development are the result of stimuli generated by the organism itself c. environmental epigenetic gene regulation only occurs in reptiles and insects, while developmental epigenetic regulation occurs in all animals d. environmental epigenetic gene regulation is typically reversible while developmental epigenetic gene regulation is typically not reversible

B. Environmental epigenetic changes can vary due to the exposure of the organism to different environmental conditions, while those programmed during development are the result of stimuli generated by the organism itself

Which of the following statements regarding epigenetic inheritance is FALSE? a. epigenetic inheritance can be reset during segregation b. epigenetic inheritance can temporarily affect an individual c. epigenetic inheritance does not involve a change in DNA sequence d. both A and B e. both B and C

B. Epigenetic inheritance can temporarily affect an individual

A genetic condition in which identical known genotypes produce a broad range of phenotypes is called _____________________. a. Penetrance b. Expressivity c. Incomplete dominance d. Incomplete penetrance

B. Expressivity

Map distance is the number of recombinant offspring divided by the total number of nonrecombinant offspring. A. true b. false

B. False

Sex limited inheritance refers to traits that are located on the X or Y chromosome. a. true b. false

B. False

The rearrangement of alleles bu the process of crossing over is called genetic linkage a. true b. false

B. False

mtDNA contains all of the genes necessary for the complete function of mitochondrial metabolism. a. true b. false

B. False

Differentially methylated regions (DMRs) are associated with which of the following? a. x-inactivation b. genomic imprinting c. maternal inheritance d. extra nuclear inheritance e. all of the above

B. Genomic imprinting

the expression of a single allele is associated with which of the following? a. x-inactivation b. genomic imprinting c. maternal inheritance d. extra nuclear inheritance

B. Genomic imprinting

Most imprinted genes are silenced. What is one exception to this rule? a. H19 b. Igf-2 c. UBE3A d. SNRPN

B. Igf-2

Another name for a chromosome is a ________________, since it contains genes that are often inherited together. a. crossing over group b. linkage group c. genetic recombination d. bivalent

B. Linkage group

If a gene is located on the X chromosome, but not the Y, it is said to be an example of _________. a. autosomal inheritance b. sex-linkage c. reciprocal cross d. pseudoautosomal inheritance e. holandric

B. Sex-linkage

Mitochondrial mutations in humans tend to affect some tissues more than others. What is the most likely explanation? a. some human tissues to not have mitochondria b. some human tissues have higher energy demands than others. c. some human tissues can synthesize large amounts of ATP in the absence of mitochondrial function d. Heteroplasmy and subsequent segreation often leads to a variegated phenotype

B. Some human tissues have higher energy demands than others

In a chi-square test to determine if two genes are linked or assorting independently, what is the default (null) hypothesis that is tested? a. the genes are linked to one another b. the genes are assorting independently c. the genes are located on the sex chromosome d. no crossing over occurs e. the distance between the genes is very small

B. The genes are assorting independently

Epistasis is ______________________. a. another term for over dominance b. when one gene can mask the expression of a second gene c. a trait that is only expressed in one sex of the species d.when two dominant alleles can be expressed in the same individual e. none of the above

B. When one gene can mask the expression of a second gene

What gene is most responsible for X-inactivation? a. Xic b. Xist c. TsiX d. Xce

B. Xist

You calculate map distance between genes A,B, and C on all pairwise dihybrid crosses. When you perform the trihybrid cross to verify your results, you discover that, despite analysis of a very large number of progeny, you have only about half as many double crossover progeny as you expect. Which explanation is the most reasonable? a. your dihybrid cross data are an underestimate of the distance between the more widely separated genes b. you are seeing an example of interference c. you are seeing an example of random sampling error d. none of the above

B. You are seeing an example of interference

How many Barr Bodies would an individual with a XXY genotype possess? a. 3 b. 2 c. 1 d. 0

C. 1

The map distance of 23.6 between two genes indicated which of the following? a. The genes are 23.6 millimeters apart b. There are 23.6 other genes between two genes of interest c. 23.6% of the offspring exhibit recombination between the two genes d. 23.6% of the offspring do not survive

C. 23.6% of the offspring exhibit recombination between the genes

A nurse cell is a. a cell without chloroplasts or mitochrondria b. a cell that destroys defective oocytes during embryogenesis c. a cell that surrounds an oocyte during early embryogenesis d. a cell that will fix a mutation in another cell e. a cell that can repair its own DNA mutations

C. A cell that surrounds an oocyte during early embryogenesis

Pattern baldness is a sex influenced trait. A woman who is heterozygous for pattern baldness marries a man who in nonbald. Which of the following would be true of their offspring? a. all would be bald b. all of the females would be nonbald, all males would be bald c. all the females would be nonbald, 1/2 of the males would be bald. d. all would be nonbald

C. All the females would be nonbald, 1/2 of the males would be bald

If a genetic disorder is X-linked recessive traits and a homozygous mutant mother married with a normal father, a. All their sons should be carriers b. half their sons should be carriers c. all their sons should show the trait d. half their sons should show the trait e. half their daughters should show the trait

C. All their sons should show the trait

A wild-type offspring are produced from a cross between parents that both display the same recessive phenotype; this genetic phenomenon is due to _________________. a. simple recessive alleles b. incomplete penetrance c. complementation d. gene dosage e. a spontaneous mutation

C. Complementation

A common way of studying methylation in cells is to sequence DNA samples before and after modification with sodium bisulfite. The sodium bisulfite deaminates cytosine residues, generating Uracil residues, therefore resulting in a change in the sequence as compared to the non-modified DNA. Sdoium bisulfite does not react with 5-methylcytosine so there will be no change in the sequence of those modified bases. When tumors are sequenced to study methylation patterns and epigenetic control, what would be the best control for sequencing using this technique? a. non-cancerous tissue DNA from a different individual but from the same organ b. liver DNA from the same individual that the cancer sample is from c. DNA from non-cancerous tissue from the same individual's organ as the cancer d. combination of DNA from liver, brain, and muscle from the same individual that has the cancer

C. DNA from non-cancerous tissue from the same individual's organ as the cancer

Sickle-cell anemia in humans is an example of _______________. a. codominance b. incomplete dominance c. heterozygous advantage d. multiple allele systems e. none of the above

C. Heterozygous advantage

A testcross is always performed between the individual that is heterozygous for the genes to be mapped and an individual who is ____________. a. heterozygous for the genes b. homozygous dominant for the genes c. homozygous recessive for the genes d. lacking the genes

C. Homozygous recessive for the genes

Polydactyly in humans is an example of ____________. a. simple Mendelian inheritance b. incomplete dominance c. incomplete penetrance d. codominance e. gene dosage

C. Incomplete penetrance

To construct a genetic map showing the relative position of genes on a chromosome, the genes under study must be _________________. a. homologous b. recessive c. linked d. mutant e. all of the above

C. Linked

For a certain trait, a heterozygous individual has a selective advantage than a homozygous dominant or homozygous recessive individual. This is called ________________. a. codominance b. incomplete dominance c. overdominance d. incomplete penetrance e. multiple allele systems

C. Overdominance

In humans, the Mic2 gene is found on both X and Y chromosomes. The inheritance pattern of this gene is the same as the inheritance pattern of the gene located on an autosome. This inheritance pattern is called _________________. a. Hemizygous inhertiance b. Sex-linked inheritance c. Pseudoautosomal inheritance d. Homozygous inheritance

C. Pseudoautosomal inheritance

What is thought to be the origin of mitochondria and chloroplast? a. cyan bacteria / purple bacteria b. purple bacteria / fungus c. purple bacteria / cyanobacteria d. algae / cyanobacteria

C. Purple bacteria/cyanobacteria

Frederick Griffith is responsible for discovering what process? a.Replication b. Transmission c. Transformation d. Transduction

C. Transformation

What is the difference between the trithorax (TrxG) and polycomb (PcG) complexes of proteins? a. TrxG proteins methylate lysine 27 on histone H3 while PcG complexes methylate lysine 4 on H3 b. methylation of lysine at position 4 on H3 results in silencing of gene expression c. TrxG complex proteins activate gene expression by methylating lysine 4 on H3, while PcG complex proteins repress gene expression by methylating lysine 27 on H3 d. methylation of H3 on lysine 27 can result in activation of transcription

C. TrxG complex proteins activate gene expression by methylating lysine 4 on H3, while PcG complex proteins repress gene expression by methylating lysine 27 on H3

The genetic control of X-inactivation is governed by a short region on the X chromosome called the a. Y-inactivation center (Yic) b. Condensation center c. X-inactivation center (Xic) d. X-initiation center

C. X-inactivation center (Xic)

Monoallelic expression of a gene: a. occurs when one copy of the gene has been deleted b. occurs when one copy of the gene carries a mutation c. occurs when the gene is imprinted d. is not seen in animals

C. occurs when the gene is imprinted

In four-o'clock plants, red flower color is dominant to white flower color. However, heterozygous plants have a pink color. If a pink-flowered plant is crossed with a white-flowered plant, what will be the phenotypic ratios of their offspring? a. 1/4 red, 1/2 pink, 1/4 white b. all pink c. all white d. 1/2 pink, 1/2 white e. 1/2 red, 1/2 pink

D. 1/2 pink, 1/2 white

If two genes are not linked, then the expected phenotypic ratio resulting from testcross is a. 9:3:3:1 b. 1:2:1 c. 3:1 d. 1:1:1:1

D. 1:1:1:1

What is a convenient way to identify gene order in a trihybrid cross? a. look for double crossover progeny and identify the gene that was flipped relative to parentals b. look for the largest class of single crossover and the two genes are the ones on the end c. look for the smallest class of single crossovers to identify the genes which are closest together d. A and B only e. all of the above

D. A and B only

For a two-point testcross, if the percentage of recombinants is over 50%, the two genes are probably ___________. a. on the same chromosome b. distant from one another on the same chromosome c. not linked d. all of the above

D. All of the above

Linked genes: a. are located near each other on the same chromosome b. violate the law of independent assortment c. segregate together during meiosis d. all of the above e. none of the above

D. All of the above

Which of the following are molecular mechanisms used in epigenetic gene regulation? a. dna methylation b. covalent histone modification c. chromatin remodeling d. all of the above

D. All of the above

cpDNA contains which of the following types of genes? a. rRNA b. tRNA c. Genes for photosynthetic pathways d. all the above e. Both rRNA and tRNA

D. All of the above

epigenetic inheritance may occur at which of the following stages? a. oogenesis b. spermatogenesis c. embryogenesis d. all of the above

D. All of the above

An example of genomic imprinting in humans is a. leber hereditart optic neuropathy b. neurogenic muscle weakness c. snail coiling in water snail d. Angelman syndrome e. bicoid gene in drosophila

D. Angelman syndrome

Lamarck is remembered for his theory of inheritance which hypothesized that physical characteristics acquired during an individuals lifetime were passed onto their offspring. How does this differ from epigenetic inheritance where the diet of the mother affects coat color of the offspring? a. there is no difference between lamarklan theories of inheritance and epigenetic inheritance b. epigenetic changes occur on a specific gene. if the mother does not carry the gene then coat color will not be affected by diet c. the change in coat color occurs in the offspring and not in the mother d. answers b and c

D. Answers B and C

Feeding a specific diet to female mice may result in an increased proportion of pseudoagouti offspring if: a. female carries the Avy allele b. offspring have genotype Avya c. transposon at the Avy locus in the progeny is hypermethylated d. answers B and C are correct

D. Answers B and C are correct

Which of the following is part of the mechanism for epigenetic regulation of the Igf-2 gene a. methylation of the H19 locus b. methylation of the ICR and DMR domains c. binding of CTC factors to methylated sequences d. answers b and c are correct e. answers a and c are correct

D. Answers B and C are correct

What gene(s) is/are encoded in the Xic? a. Xce b. Xist c. Tsix d. both Tsix and Xist are genes in the Xic region

D. Both Tsix and Xist are genes in the Xic region

A modification that occurs to a nuclear gene that alters gen expression, but not permanently, is called ----- inheritance. a. extranuclear b. cytoplasmic c. maternal effect d. epigenetic e. nuclear

D. Epigenetic

A male is produced from an unfertilized haploid egg is an example of what type of sex determination system? a. X-Y b. Z-W c. X-O d. Haplo-diploid e. none of the above

D. Haplo-diploid

A heterozygote possesses a phenotype that is intermediate between the homozygous dominant and homozygous recessive phenotype. This is most likely an example of _______________. a. lethal alleles b. sex-influenced inheritance c. gene dosage d. incomplete dominance

D. Incomplete dominance

The inheritance of leaf pigmentation on the four-o'clock plant Mirabilis jalapa is an example of ________. a. maternal effect b. imprinting c. epigenic inheritance d. maternal inheritance e. none of the above

D. Maternal inheritance

The current molecular explanation for imprinting in mammals involves differential _________ of various DNA regions. a. phosphorylation b. mutations c. endosymbiosis d. methylation e. heteroplasmy

D. Methylation

What is the molecular mechanism for imprinting a gene? a. acetylation b. nitration c. phosphorylation d. methylation

D. Methylation

During a crossing over event, which of the following would be involved in the genetic exchange? a. parts of two non-homologous chromosomes b. parts of all four homologs c. parts of two sister chromatids d. parts of two of the four homologs

D. Parts of two of the four homologs

The frequency with which individuals of a given genotype (i.e. a dominant or homozygous recessive) manifest at least some degree of a specific mutant phenotype associated with a trait is called ___________. a. Homozygous dominant b. Homozygous recessive c. Expressivity d. Penetrance

D. Penetrance

In a group of fruit flies homozygous for an allele that causes a reduced number of thoracic, bristles, you notice that the number of bristles varies from about half the normal number to only a few bristles. This is an example of which of the following? a. incomplete dominance b. overdominance c. incomplete penetrance d. variable expressivity

D. Variable expressivity

The fact that the type IIR and IIIS strains of Streptococcus pneumoniae that Griffith worked with possessed small differences in capsule structure satisfies which of the following criteria for genetic material? a. Transmission b. Replication c. Information d. Variation

D. Variation

X, Y, and Z are linked genes. Based on testcross data, the frequency of recombination between genes X and Y was found to be 33.1 map units; between genes X and Z the distance was 11.8 map units; and between genes Y and Z the distance was 21.3 map units. What is the order of these genes on the chromosome? a. X-Y-Z b. Z-Y-X c. Y-X-Z d. X-Z-Y

D. X-Z-Y

Heteroplasmy is associated with inheritance patterns involving ______________. a. ribosomes b. maternal effect c. genomic imprinting d. nuclear genes e. chloroplasts

E. Chloroplasts

In human blood groups, the fact that an individual can have an AB blood type is an example of ________. a. incomplete dominance b. incomplete penetrance c. sex-influenced trait d. temperature-sensitive conditional allele e. codominance

E. Codominance

In a dihybrid cross of two heterozygous individuals, you expect a 9:3:3:1 phenotypic ratio in the offspring, but observe a ratio of 9:7. What is the most likely explanation? a. codominance b. it is a sex-limited trait c. Simple Mendelian inheritance d. Incomplete dominance e. Epistatic interactions of the two genes

E. Epistatic interactions of the two genes

If a combination of two or more genes is required to produce a specific trait, it is called a _____________. a. overdominance b. simple Mendelian trait c. sex-influenced trait d. sex-linked trait e. gene interaction

E. Gene interaction

Where is extra nuclear DNA located in mammalian cells? a. endoplasmic reticulum b. chloroplasts c. ribosomes d. plasma membrane e. mitochondria

E. Mitochondria

If an allele is dominant in one sex and recessive in another, it is an example of _______________. a. sex-limited inheritance b. incomplete dominance c. incomplete penetrance d. simple Mendelian inheritance e. sex-influenced inheritance

E. Sex-influenced inheritance

The multiple effects of a single gene on the phenotype of an organism are called ___________. a. epistasis b. penetrance c. expressivity d. overdominance e. pleiotrophy

E. pleiotrophy

In the gene that affects snail coiling, the ______ is responsible for the phenotype of the offspring.

Mother's genotype

Which of the following is primarily responsible for the maternal effect?

Nurse cells

Expression of ---- would inhibit X-inactivation. a. Xic b. Xist c. Tsix d. all of the above d. none of the above

c. Tsix

The coat color of calico cats is a result of ___________. a. maternal inheritance b. extra nuclear inheritance c. imprinting d. X-inactivation

d. X-inactivation