- What is genomic imprinting?
- A) The process of DNA replication
- B) The preferential expression of one allele based on parent-of-origin
- C) The recombination of genetic material
- D) The duplication of chromosomal segments
Answer: B – Genomic imprinting refers to the preferential expression of one allele based on whether it is inherited from the mother or the father.
- Which of the following is a key feature of genomic imprinting?
- A) It involves the inheritance of dominant traits only.
- B) It leads to the expression of both alleles from a gene.
- C) It is regulated by DNA methylation and histone modification.
- D) It occurs only in female individuals.
Answer: C – Genomic imprinting is regulated by epigenetic mechanisms, including DNA methylation and histone modification.
- Which genetic disorder is associated with improper genomic imprinting?
- A) Cystic fibrosis
- B) Prader-Willi syndrome
- C) Sickle cell anemia
- D) Down syndrome
Answer: B – Prader-Willi syndrome is an example of a disorder caused by the loss of expression of a paternal allele due to genomic imprinting.
- Imprinting disorders result from defects in:
- A) Chromosome number
- B) The DNA sequence itself
- C) The regulation of gene expression
- D) The replication of DNA
Answer: C – Imprinting disorders arise due to defects in the regulation of gene expression rather than changes in the DNA sequence.
- Which of the following best describes the mechanism of genomic imprinting?
- A) Both alleles are expressed equally.
- B) One allele is silenced based on its parent of origin.
- C) Both alleles are mutated and cause disease.
- D) One allele is duplicated.
Answer: B – In genomic imprinting, one allele is silenced depending on whether it is inherited from the mother or the father.
- Which of the following is most directly responsible for silencing one allele during imprinting?
- A) Gene duplication
- B) DNA methylation
- C) Protein degradation
- D) mRNA splicing
Answer: B – DNA methylation plays a key role in silencing one allele during the process of genomic imprinting.
- Which of the following diseases is associated with the loss of expression of the maternal allele?
- A) Prader-Willi syndrome
- B) Angelman syndrome
- C) Huntington’s disease
- D) Turner syndrome
Answer: B – Angelman syndrome is associated with the loss of expression of the maternal allele due to genomic imprinting.
- What is the effect of the loss of a paternal allele in Prader-Willi syndrome?
- A) Overexpression of a gene leading to obesity
- B) Loss of function of certain genes leading to intellectual disabilities
- C) Loss of function of genes resulting in uncontrollable laughter
- D) Normal development
Answer: B – In Prader-Willi syndrome, the loss of the paternal allele results in intellectual disabilities and other physical effects.
- Which epigenetic modification is primarily involved in genomic imprinting?
- A) Acetylation
- B) Methylation
- C) Phosphorylation
- D) Ubiquitination
Answer: B – Methylation is the primary epigenetic modification involved in genomic imprinting, leading to gene silencing.
- In genomic imprinting, which of the following determines which allele is imprinted?
- A) The chromosomal position of the gene
- B) The gender of the offspring
- C) The parent from whom the allele is inherited
- D) The presence of a mutation in the gene
Answer: C – The parent from whom the allele is inherited determines whether it is imprinted and silenced.
- Which of the following statements about genomic imprinting is false?
- A) Imprinting involves the silencing of one allele.
- B) Both alleles from the mother and father are expressed equally.
- C) Imprinting disorders result from the loss of function of imprinted genes.
- D) Imprinting is regulated by epigenetic modifications.
Answer: B – In genomic imprinting, one allele is silenced depending on the parent of origin, so they are not expressed equally.
- What does the term “parental imprinting” refer to?
- A) The expression of only the maternal allele
- B) The expression of only the paternal allele
- C) Both alleles being expressed equally
- D) The process of chromosome duplication
Answer: B – Parental imprinting refers to the expression of only the paternal allele, with the maternal allele being silenced.
- What is the primary consequence of improper genomic imprinting in offspring?
- A) Misalignment of chromosomes
- B) Mutations in DNA sequences
- C) Imbalanced gene expression
- D) Increased chromosome number
Answer: C – Improper genomic imprinting leads to imbalanced gene expression, which can result in developmental disorders.
- Which of the following is a mechanism that can disrupt genomic imprinting?
- A) DNA replication errors
- B) Mutations in imprinting control regions
- C) Errors in meiosis
- D) Both B and C
Answer: D – Both mutations in imprinting control regions and errors in meiosis can disrupt genomic imprinting.
- What is the relationship between genomic imprinting and X-inactivation in females?
- A) Both are examples of chromosomal duplication events.
- B) Both involve the silencing of one allele in females.
- C) Both occur during meiosis only.
- D) Both are unrelated processes.
Answer: B – Both genomic imprinting and X-inactivation involve the silencing of one allele in females, though X-inactivation occurs in female mammals to balance gene expression between sexes.
- Which of the following is true about genomic imprinting in mammals?
- A) It is a process that only affects the maternal genome.
- B) The imprinted allele is always the one inherited from the father.
- C) Imprinting involves reversible modifications to DNA.
- D) Only the paternal allele is expressed in all genes.
Answer: C – Genomic imprinting involves reversible modifications to DNA, such as methylation, which regulate allele expression.
- What causes the phenotypic differences in Prader-Willi syndrome and Angelman syndrome despite both having the same chromosomal deletion?
- A) The location of the mutation
- B) Imprinting on the chromosome region
- C) The age of the individual
- D) The sex of the individual
Answer: B – The phenotypic differences arise because of the parental origin of the deletion, with Prader-Willi syndrome occurring from a lack of paternal gene expression and Angelman syndrome from a lack of maternal gene expression.
- What does the imprinting control region (ICR) do?
- A) It causes the duplication of imprinted genes.
- B) It regulates the methylation of certain genes in the genome.
- C) It prevents recombination during meiosis.
- D) It activates genes during embryonic development.
Answer: B – The imprinting control region (ICR) regulates the methylation of genes involved in genomic imprinting.
- Which of the following best describes the inheritance pattern of imprinted genes?
- A) Both alleles are always expressed.
- B) One allele is silenced based on the parent of origin.
- C) Both alleles are silenced.
- D) Both alleles are mutated.
Answer: B – One allele is silenced based on whether it is inherited from the mother or father in the process of genomic imprinting.
- Which of the following mechanisms can result in the loss of imprinting?
- A) DNA hypomethylation
- B) DNA hypermethylation
- C) Chromosomal translocation
- D) All of the above
Answer: D – DNA hypomethylation, hypermethylation, and chromosomal translocation can all result in the loss of imprinting, leading to various disorders.
- Which of the following genes is known to be imprinted in humans?
- A) The Hox gene
- B) The IGF2 gene
- C) The TP53 gene
- D) The BRCA1 gene
Answer: B – The IGF2 gene (insulin-like growth factor 2) is known to be imprinted in humans, with expression depending on the parental origin.
- In the context of genomic imprinting, which of the following is a maternal effect?
- A) The loss of the paternal allele in Prader-Willi syndrome
- B) The silencing of the paternal allele in Angelman syndrome
- C) The expression of only the maternal allele
- D) The deletion of a gene from both parents
Answer: B – In Angelman syndrome, the maternal allele is affected, leading to the silencing of the paternal allele.
- Which of the following conditions is NOT typically associated with genomic imprinting disorders?
- A) Growth defects
- B) Intellectual disabilities
- C) Muscle weakness
- D) Diabetes
Answer: D – Diabetes is not typically associated with genomic imprinting disorders, while growth defects, intellectual disabilities, and muscle weakness are common features.
- What would be the effect of a mutation in the imprinting control region (ICR) of a gene?
- A) Complete inactivation of the gene
- B) Loss of parental-specific gene expression
- C) Reversal of X-inactivation
- D) Increased gene expression
Answer: B – A mutation in the imprinting control region (ICR) could lead to the loss of parental-specific gene expression, causing imprinting disorders.
- Which is a common feature of both Prader-Willi syndrome and Angelman syndrome?
- A) Both are caused by mutations in the same gene.
- B) Both involve chromosome 15 deletions.
- C) Both are associated with intellectual disabilities.
- D) All of the above.
Answer: D – Both Prader-Willi syndrome and Angelman syndrome involve deletions in chromosome 15, are associated with intellectual disabilities, and may share some clinical features.
- In genomic imprinting, which of the following is a consequence of improper silencing of an allele?
- A) The gene is overexpressed.
- B) The gene becomes mutated.
- C) The gene is underexpressed.
- D) The gene is not inherited.
Answer: C – Improper silencing of an allele can lead to its underexpression, which can result in diseases or disorders.
- What role do non-coding RNAs play in genomic imprinting?
- A) They help in gene expression by inhibiting transcription.
- B) They regulate DNA methylation patterns in imprinting control regions.
- C) They cause mutations in the imprinted genes.
- D) They replicate the imprinted genes.
Answer: B – Non-coding RNAs can regulate DNA methylation patterns in imprinting control regions, affecting the imprinting process.
- What is a likely outcome of errors in the DNA methylation patterns of imprinted genes?
- A) Normal gene expression
- B) Loss of imprinting disorders
- C) Decreased chromosomal instability
- D) Chromosome duplication
Answer: B – Errors in DNA methylation patterns of imprinted genes often lead to loss of imprinting disorders, causing developmental abnormalities.
- How is the imprinted gene IGF2 related to fetal growth?
- A) It is involved in brain development.
- B) It regulates glucose metabolism.
- C) It controls growth via the insulin-like growth factor pathway.
- D) It affects bone density.
Answer: C – IGF2 regulates fetal growth through the insulin-like growth factor pathway, and its imprinting affects growth patterns.
- What is a hallmark of diseases caused by genomic imprinting?
- A) Increased gene expression from both alleles
- B) Parent-of-origin specific gene expression errors
- C) Mutations in only one allele
- D) Genetic recombination
Answer: B – A hallmark of diseases caused by genomic imprinting is the disruption of parent-of-origin specific gene expression.
