Question

Which of the following statements about CpG islands is correct?a. CpG islands are commonly found at the 3′ UTR regions.b. The CpG island methylation is universal across both prokaryotes and eukaryotes.c. Methylated CpG islands is associated with long term gene repression.d. Transcriptionally active DNA has higher frequency of methylated CpG.e. There is an association exists between DNA methylation at the CpG island and acetylation of histone via recruitment of acetylases.

Answer 1

Answer:

c. Methylated CpG islands is associated with long term gene repression.

Explanation:

The CpG sites or islands is a biological term that describes the genomic regions in which CpG sites occur; a region of DNA, in which cytosine nucleotide is followed by a guanine nucleotide in the linear sequence of bases along its 5' → 3' direction.

The CpG islands is characterized with a high frequency of CpG sites, with at least 200 bp, a GC percentage greater than 50%, and an observed-to-expected CpG ratio greater than 60%.

The existence of CpG islands is also associated with low levels of methylation in that genomic area, which has to do with the regulation or repression of gene expression