Epigenetic inheritance transmits gene-expression states without DNA sequence change when tags persist through cell division or reproduction across generations and tissues.
Epigenetic inheritance transmits a gene-expression state without transmitting a new DNA base sequence.
During DNA replication, each daughter DNA molecule initially contains one parental strand carrying the previous local methylation pattern and one newly synthesized strand.
Maintenance enzymes recognize those local cues and restore methylation or chromatin features on the new material, so daughter cells inherit a similar regulatory state.
This cellular memory helps a dividing liver cell lineage remain different from a dividing skin or muscle cell lineage even though their genomes are very similar.
Persistence through mitosis is not the same as transmission to offspring. Gamete development and early embryos erase many epigenetic marks.
During germ-cell development and early embryonic development, extensive epigenetic reprogramming removes most existing tags so the new organism can establish appropriate developmental expression patterns.
Evidence that an epigenetic mark persists in a person's somatic cells does not by itself show that the mark will pass through gametes to descendants.
shared genome → cell-specific regulatory and epigenetic state → cell-specific transcriptome → cell-specific proteome → differentiated structure and function
| Process | What remains continuous? | What can change? |
|---|---|---|
| mitosis in a differentiated lineage | much of the expression state | reversible tags and regulatory inputs |
| environmental response | DNA base sequence usually remains | signalling, transcription and sometimes epigenetic marks |
| gamete and early-embryo reprogramming | genome and selected imprints | most parental epigenetic patterns are reset |
For any epigenetic claim, ask where the tag is, how it changes access or protein binding, whether it persists through mitosis or gametes, and whether the evidence shows correlation or causation.