\[ **BT: [[genetics]]** ] --- # epigenetics > [[‘Modern epigenetic research has proven what witches, shamans, and wise folk have always known— that the experiences of our ancestors are handed down and live on in us today.’]][^1] Epigenetics is the study of changes in gene activity which are *not* caused by changes in the [[genetics#DNA|DNA]] sequence.[^2] It is interested in [[#gene expression]]; that is, how genes bring about an individual organism’s [[genetics#phenotype|phenotype]].[^3] Sometimes, changes in how genes are expressed (or suppressed) may last for the rest of the cell’s life—or for generations of cells (i.e. through cell divisions). However, *there is no change to the individual’s underlying DNA sequence.*[^4] ## epigenetic traits Genetic traits are a ‘stably heritable [[#phenotype]] resulting from changes in a chromosome *without alterations in the DNA sequence*’.[^5] ## epigenome An organism’s epigenome is the ‘collection of chemical changes to its DNA and histone proteins that affects when, where, and how the DNA is expressed’. These changes can be passed down to the organism’s offspring via **transgenerational epigenic inheritance**.[^6] ## genomic imprinting Genomic imprinting is the process of *tagging a gene for the lifetime of the individual organism*; that is, switches the gene off (or on). Usually in the way that is more favourable the individual.[^7] Genomic imprinting causes genes to be expressed (or not) depending on whether they were inherited from the female or male parent.[^8] It is different from [[#mutation]]. There are three main theories about the hows/whys of genomic imprinting: - **Haig et al.’s kinship theory** ([Haig and Westoby, 1989](https://pmc.ncbi.nlm.nih.gov/articles/PMC4105453/#bib27); [Haig, 2000a](https://pmc.ncbi.nlm.nih.gov/articles/PMC4105453/#bib21), [2004](https://pmc.ncbi.nlm.nih.gov/articles/PMC4105453/#bib24)) - **Day and Bonduriansky’s sexual antagonism theory** ([Day and Bonduriansky's (2004)](https://pmc.ncbi.nlm.nih.gov/articles/PMC4105453/#bib10); see also [Bonduriansky, 2007](https://pmc.ncbi.nlm.nih.gov/articles/PMC4105453/#bib3)) - **Wolf and Hager’s maternal–offspring co-adaption theory** ([Wolf and Hager's (2006)](https://pmc.ncbi.nlm.nih.gov/articles/PMC4105453/#bib73); see also [Wolf and Hager, 2009](https://pmc.ncbi.nlm.nih.gov/articles/PMC4105453/#bib74); [Wolf, 2013](https://pmc.ncbi.nlm.nih.gov/articles/PMC4105453/#bib68)) All three theories rest on different logic and assumptions; that said, they share a critical common feature: the belief that ‘some process creates a selective symmetry between the maternally and paternally inherited allelic copies at a locus that causes selection to favour differential expression of the alleles’ (typically silencing one of them).[^9] Imprinting seems to have evolved only about 150 million years ago in animals, and is largely confined to [[mammals]].[^10] --- ## epigenetic processes ### DNA methylation A mechanism via which gene expression may be suppressed.[^11] ### histone modification --- ## switched-off genes ### switched-off genes in humans - [[Hominins once had penile spines... extremely long ago (prior to the emergence of Neanderthals).]][^12] + [[Humans have the latent ability to 'regenerate damaged sensory organs like the eye'; however, the gene is switched off.]][^13] [^1]: Amber Magnolia Hill, ‘[[Hill, ‘Story is Medicine’, 2018|Story is Medicine: The Mythic Imagination on the Healing Path]], *Plant Healer*, vol. 8, no. 2 (2018), p. 100, <https://issuu.com/planthealer/docs/phm-30>. [^2]: ‘Epigenetics’, \[Simple English] Wikipedia, last edited 11 June 2023, 13:21 (UTC), <https://simple.wikipedia.org/wiki/Epigenetics>. [^3]: ‘Epigenetics’, \[Simple English] Wikipedia, last edited 11 June 2023, 13:21 (UTC), <https://simple.wikipedia.org/wiki/Epigenetics>. [^4]: ‘Epigenetics’, \[Simple English] Wikipedia, last edited 11 June 2023, 13:21 (UTC), <https://simple.wikipedia.org/wiki/Epigenetics>. [^5]: ‘Epigenetics’, \[Simple English] Wikipedia, last edited 11 June 2023, 13:21 (UTC), <https://simple.wikipedia.org/wiki/Epigenetics>. [^6]: ‘Epigenome’, Wikipedia, last edited 8 August 2024, 0:203 (UTC), <https://en.wikipedia.org/wiki/Epigenome>. [^7]: ‘Epigenetics’, \[Simple English] Wikipedia, last edited 11 June 2023, 13:21 (UTC), <https://simple.wikipedia.org/wiki/Epigenetics>. [^8]: ‘Genomic imprinting’, Wikipedia, last edited 12 December 2024, 09:02 (UTC), <https://en.wikipedia.org/wiki/Genomic_imprinting>. [^9]: M. M. Patten et al., ‘[[Patten et al., ‘The Evolution of Genomic Imprinting’, 2014|The Evolution of Genomic Imprinting: Theories, Predictions and Empirical Tests]]’, *Heredity (Edinb.)*, vol. 113, no. 2 (2014), pp. 119–128, <https://doi.org/10.1038/hdy.2014.29>. [^10]: ‘Epigenetics’, \[Simple English] Wikipedia, last edited 11 June 2023, 13:21 (UTC), <https://simple.wikipedia.org/wiki/Epigenetics>. [^11]: ‘Epigenetics’, \[Simple English] Wikipedia, last edited 11 June 2023, 13:21 (UTC), <https://simple.wikipedia.org/wiki/Epigenetics>. [^12]: ‘Genetics’, Wikipedia, last edited 20 March 2026, 13:53 (UTC), <https://en.wikipedia.org/wiki/Genetics>. [^13]: ‘Genetics’, Wikipedia, last edited 20 March 2026, 13:53 (UTC), <https://en.wikipedia.org/wiki/Genetics>.