Podcast
Questions and Answers
Which of the following best describes the relationship between genetics and epigenetics?
Which of the following best describes the relationship between genetics and epigenetics?
- Epigenetics directly modifies the DNA sequence, leading to permanent genetic mutations.
- Epigenetics operates independently of the genome, focusing solely on environmental influences.
- Epigenetics replaces classical genetics as the primary explanation for inherited traits.
- Epigenetics explains variations in gene expression without altering the underlying DNA sequence. (correct)
Conrad Waddington's concept of epigenetics primarily addresses which biological phenomenon?
Conrad Waddington's concept of epigenetics primarily addresses which biological phenomenon?
- The direct alteration of DNA sequences by environmental factors.
- The exclusive role of non-coding RNAs in controlling gene expression.
- The process by which mutations arise spontaneously in a population.
- The interaction between genes and their products leading to the development of a phenotype. (correct)
Which of the following epigenetic mechanisms is associated with the silencing of genes?
Which of the following epigenetic mechanisms is associated with the silencing of genes?
- Methylation of DNA in CpG islands located in the promoter region. (correct)
- Destruction of the passenger strand of microRNA.
- Phosphorylation of histone tails.
- Acetylation of histone tails.
How does histone acetylation influence gene expression?
How does histone acetylation influence gene expression?
During early embryonic development, what epigenetic change typically occurs to activate transcription?
During early embryonic development, what epigenetic change typically occurs to activate transcription?
What is the primary role of mature microRNA (miRNA) in gene expression?
What is the primary role of mature microRNA (miRNA) in gene expression?
Which enzyme is directly involved in the process of DNA methylation?
Which enzyme is directly involved in the process of DNA methylation?
A researcher observes increased levels of histone methylation in a specific gene region. What is the likely effect on gene expression in that region?
A researcher observes increased levels of histone methylation in a specific gene region. What is the likely effect on gene expression in that region?
Which of the following is NOT a key mechanism in epigenetic regulation?
Which of the following is NOT a key mechanism in epigenetic regulation?
How are nucleosomes related to epigenetic modifications?
How are nucleosomes related to epigenetic modifications?
Flashcards
Epigenetics
Epigenetics
Changes in gene expression independent of changes in DNA sequence.
DNA Methylation
DNA Methylation
Addition of methyl groups onto cytosine nucleic acids in CpG islands, often leading to gene silencing.
Histone Proteins
Histone Proteins
DNA is wrapped around these proteins and the histone tails can be modified to increase or decrease packing.
Histone Modification
Histone Modification
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MicroRNA (miRNA)
MicroRNA (miRNA)
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RISC (RNA-induced silencing complex)
RISC (RNA-induced silencing complex)
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DNA methyltransferase
DNA methyltransferase
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Conrad Waddington
Conrad Waddington
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Study Notes
- Epigenetics refers to modifications "above" or "in addition to" genetics.
- It explores the relationship between genes and the environment.
- Epigenetics explains occurrences that traditional genetics could not.
- Conrad Waddington coined the term epigenetics.
- According to Waddington, epigenetics explains gene and gene product interactions that result in a phenotype.
- Epigenetics examines changes in gene expression that occur without changes to the DNA sequence.
- DNA methylation, histone modification/chromatin remodeling, and non-coding RNAs (ncRNAs) are factors in the mechanism of forming the code to function.
- DNA code leads to transcription, then translation, then functional proteins.
- Epigenetic variation occurs between transcription and translation.
DNA Methylation
- DNA methylation involves adding methyl groups to cytosine nucleic acids in CpG islands.
- The DNA methyltransferase enzyme processes this.
- It occurs on the promoter upstream of a gene.
- It is associated with gene silencing.
Nucleosomes
- Nucleosomes consist of DNA wrapped around histone proteins.
- Histone tails protrude outward from the proteins and undergo modifications.
- Methylation increases packing.
- Acetylation decreases packing.
- Phosphorylation decreases packing.
Histone Modification in Early Development
- Transcription is initially low, and histones are methylated.
- Histones are acetylated, activating transcription.
- Modifications are regulated by the zygotic genome.
Micro RNA
- Micro RNA is created in the nucleus and then moves to the cytoplasm.
- Double strands become single strands.
- One strand, the passenger strand, is destroyed.
- The other strand becomes mature micro RNA.
- This leads to RNA-induced silencing complex or translation repression.
Summary of Epigenetics
- Epigenetics involves changes in gene expression independent of changes in DNA sequence.
- Mechanisms include DNA methylation, histone modifications/chromatin remodeling, and noncoding RNA.
- These mechanisms are crucial for proper embryonic development.
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