Choose the correct explanation why CpG islands might have come to be underrepres
ID: 211258 • Letter: C
Question
Choose the correct explanation why CpG islands might have come to be underrepresented in eukaryotic genomes.
A. CpG sites are frequently methylated and 5-methylcytosine residues undergo spontaneous deamination which generates thymidine. Upon replication a methyl-dC-G base pair becomes a T-A pair. B. CpG sites are frequently methylated and 5-methylcytosine residues undergo spontaneous deamination which generates uracil. Upon replication a methyl-dC-G base pair becomes a T-A pair. C. CpG sites are frequently methylated and 5-methylcytosine residues undergo spontaneous deamination which generates uracil. Upon reparation a methyl-dC-G base pair becomes a T-A pair. D. CpG sites are frequently methylated and 5-methylcytosine residues are oxidized to 5-hydroxymethylcytosine. Upon reparation a methyl-dC-G base pair becomes a T-A pair.Explanation / Answer
correct answer: (a) CpG sites are frequently methylated and 5-methylcytosine residues undergo spontaneous deamination which generates thymidine. Upon replication a methyl-dc-g base pair becomes as T-A pair.
Explanation: CpG island are almost located within or in the proximity of promoter regions which is move towards the transcribed areas sometimes, in comparison with umnethylated CpGs are alwaus invoved with transcription activity. There hyper methylated conditions are sometime obsereved in carcinogenesis and gene between them is directly slicening either by sterically hindering transcription factor binding or by methyl binding repressor protein interaction indirectly which results in chromatin modification because of this it is difficult to achieve dese chromatin state. But the mutation and gene silencing become avoidance of CpG while in constructing recomdinant protein production and gene therapy by designing expression.