Explain the role of epigenetic inheritance in gene expression.

• A. Epigenetic marks are permanent and cannot be inherited.
• B. Epigenetic marks such as DNA methylation and histone modifications can be transmitted during cell division, influencing gene expression in daughter cells.
• C. Epigenetic marks change DNA sequence.
• D. Epigenetic marks are only relevant in germ cells.

Answer: (B)

Epigenetic inheritance is about how gene expression can be passed from a cell to its daughter cells without changing the actual DNA sequence. The key idea is that chemical marks on DNA and on histone proteins—such as DNA methylation and various histone modifications—can be preserved and copied when a cell divides. During DNA replication, maintenance enzymes ensure methylation patterns are copied to the new DNA strand, helping daughter cells retain the same gene expression programs. Histone marks help re-establish the same chromatin state on the new strands, guiding which genes are active or repressed in the offspring cells. This maintenance of marks across cell divisions allows a tissue to keep its identity and function as it grows or renews itself.

While some epigenetic information can be reset during development or gametogenesis, many marks are faithfully inherited during mitosis, influencing how genes are expressed in daughter cells. This is the essence of why epigenetic regulation matters for development, cellular memory, and responses to environmental cues. The statement that epigenetic marks like DNA methylation and histone modifications can be transmitted during cell division, influencing gene expression in daughter cells, best captures how this inheritance works. The other options misrepresent the concept: epigenetic marks do not alter the DNA sequence themselves, they are not permanently unchangeable, and they are not limited to germ cells.