P is true: oncogenic viruses can alter cell-cycle regulation or promote other carcinogenic processes. Q is true because epigenetic silencing, for example promoter methylation, can repress a tumor suppressor without changing its nucleotide sequence. R is true because miRNAs regulate target mRNAs and their dysregulation can affect oncogenes and tumor suppressors. All three are correct, D.
More Molecular Biology: Structure of genes and chromosomes, mutations and mutagenesis, regulation of gene expression questions
GATE 2019 BT Q21– A mutation produces a variant polypeptide lacking the last three amino acids. What type of…