Which statement best describes the relationship between genomes and epigenomes?

• A. They are identical
• B. Genomes determine trait expression; epigenomes contain DNA sequences
• C. Genomes contain DNA sequences; epigenomes determine trait expression
• D. Epigenomes replace genomes in adulthood

Answer: (C)

The main idea here is how the genetic blueprint and its regulation relate to trait expression. The genome contains the DNA sequences that form the blueprint of an organism. The epigenome consists of chemical marks and modifications that regulate how those instructions are read without changing the actual DNA sequence. These epigenetic signals can turn genes on or off or modulate their level of expression, and they can change with development, environment, and age. Because of this, trait expression is shaped by how the genome is read, not by the genome alone. That’s why the correct view is that genomes contain DNA sequences while epigenomes determine trait expression. The other statements don’t fit because epigenomes don’t contain the DNA sequence itself, they don’t replace the genome, and they aren’t identical to the genome.