A 34-year-old woman was recently diagnosed with colon cancer…

A 34-yeаr-оld wоmаn wаs recently diagnоsed with colon cancer. Her father has been previously treated for colon cancer. Her identical twin sister has not been diagnosed with any malignancy. The twins have essentially identical DNA sequences, yet only one has developed cancer. Name the epigenetic modification most likely to have accumulated differently between the sisters, and explain how it could contribute to colon cancer in one twin but not the other. Reference gene silencing and the class of genes involved. Explain why epigenetic modifications can be reversed while DNA sequence mutations cannot, and identify the type of intervention capable of reversing an established modification. Genomic imprinting, histone modification, and chromatin structure are also epigenetic phenomena. Briefly state why none of them accounts for lifestyle-driven divergence between individuals with identical sequences.