112. Given below are two statements:
Statement I: CpG islands are sequences present in eukaryotic DNA.
Statement II: Promoter regions of many expressed genes in eukaryotes are generally enriched in CpG
islands.
In the light of the above statements, choose the correct answer from the options given below
1. Both Statement I and Statement II are true
2. Both Statement I and Statement II are false
3. Statement I is correct but Statement II is false
4. Statement I is incorrect but Statement II is true

Question:

Given below are two statements:

• Statement I: CpG islands are sequences present in eukaryotic DNA.

• Statement II: Promoter regions of many expressed genes in eukaryotes are generally enriched in CpG islands.

In light of the above statements, choose the correct answer from the options given below:

1. Both Statement I and Statement II are true

2. Both Statement I and Statement II are false

3. Statement I is correct but Statement II is false

4. Statement I is incorrect but Statement II is true

Correct Answer:

1. Both Statement I and Statement II are true

Explanation:

Statement I: CpG islands are sequences present in eukaryotic DNA.
This statement is correct. CpG islands are regions of DNA that have a high frequency of cytosine and guanine nucleotides linked by a phosphodiester bond, specifically in the context of the “CpG” dinucleotide. These islands are generally found in eukaryotic genomes, particularly in the promoter regions of genes.

Statement II: Promoter regions of many expressed genes in eukaryotes are generally enriched in CpG islands.
This statement is also correct. In eukaryotic cells, promoter regions of actively expressed genes often have CpG islands that are relatively unmethylated. These unmethylated CpG islands are associated with active transcription, as they help in the binding of transcription factors and the recruitment of the transcriptional machinery.

Conclusion:

Both statements accurately describe CpG islands and their role in the gene expression process. CpG islands are indeed present in eukaryotic DNA, and their enrichment in promoter regions is a common feature of many expressed genes.

Correct Answer: 1. Both Statement I and Statement II are true