Multiple Choice
Which of the following events results in X-inactivation in female mammals?
4
views
3. Extensions to Mendelian Inheritance
X-Inactivation
Struggling with Genetics?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
When CpG islands are unmethylated during X-inactivation, which of the following is most likely to occur?
A
The associated gene is permanently silenced.
B
The XIST gene is repressed.
C
Histone proteins are ubiquitinated at the promoter region.
D
The associated gene is transcriptionally active.
Verified step by step guidance1
Understand the role of CpG islands in gene regulation: CpG islands are regions rich in cytosine and guanine nucleotides linked by a phosphate bond, often found near gene promoters and are key sites for DNA methylation.
Recall that DNA methylation of CpG islands typically leads to gene silencing by preventing transcription factor binding or recruiting proteins that compact chromatin.
Recognize that during X-inactivation, methylation of CpG islands on the inactive X chromosome contributes to stable gene silencing, while unmethylated CpG islands are associated with active gene expression.
Connect the unmethylated state of CpG islands to an open chromatin configuration, which allows transcription machinery to access the gene promoter, leading to transcriptional activity.
Conclude that if CpG islands remain unmethylated during X-inactivation, the associated gene is most likely to be transcriptionally active rather than silenced.
Related Videos
Related Practice
