Genetics vs Epigenetics: What You Inherit and What You Can Change
Your DNA sequence tells you what you were dealt. Your epigenome shows how your body is playing that hand today. Each answers a different question — and they are most useful together.
KEY POINTS
- Genetics is the DNA sequence you inherit. It stays essentially the same throughout life.
- Epigenetics is the layer of marks that controls gene activity. It changes with age, exposures and lifestyle.
- Genetic testing shows inherited predispositions; epigenetic testing shows current biological activity.
- Genes are not destiny — but some genetic findings need medical follow-up, whatever your lifestyle.
Genetics: the sequence you inherit
Your genome is the full sequence of DNA you inherit — half from each parent. Apart from rare changes that build up in individual cells over a lifetime, it stays the same from birth.
Some variants have large effects: inherited BRCA1 or BRCA2 mutations, for example, raise the lifetime risk of breast cancer to around 70%. Most common conditions, however, are influenced by thousands of variants with small effects, which can be combined into a polygenic risk score.
Whole genome sequencing reads all of your DNA, rather than a selected panel of genes, so it can capture both kinds of risk.
Epigenetics: how active your genes are now
The epigenome is the set of chemical marks — such as DNA methylation — that controls which genes are used, and how much. It differs between tissues, changes with age, and responds to exposures such as smoking, diet, activity and stress.
If genetics tells you which risks you carry, epigenetics helps show which biological processes look more active today.
Side by side
| Genetics | Epigenetics | |
|---|---|---|
| What it is | Your DNA sequence | Chemical marks that control gene activity |
| Changes over life? | Essentially no | Yes — with age, exposures and lifestyle |
| Tells you | Inherited predispositions | Current biological activity, including biological age |
| Same in every tissue? | Yes | No — it differs from tissue to tissue |
| How it is measured | DNA sequencing | DNA methylation analysis |
Genes are not destiny
Identical twins share the same DNA, yet studies have shown that their epigenomes become more different as they age, and that they often develop different diseases. Estimates of how much lifespan is inherited have also come down: a large study of family trees suggested that the heritability of human lifespan is likely below 10%.
That does not make genetics unimportant. Some inherited variants call for specific screening or medical care, and genetic results should be discussed with a qualified professional — and, where appropriate, a genetic counsellor.
Why read both?
A genetic predisposition tells you where to look. An epigenetic profile adds information about what is happening now. Combining the two helps focus prevention on the areas that matter most for each person, and track whether it is working.
Watch a longer conversation
Evidence at a glance
ESTABLISHED SCIENCE
- The DNA sequence is inherited and stays largely the same through life.
- Some single-gene variants, such as in BRCA1/2, carry high disease risk.
- Identical twins diverge epigenetically with age.
EMERGING RESEARCH
- How best to combine polygenic scores and epigenetic measures for individual prevention.
- How much of aging is explained by genes versus environment.
HOW EPIX AI USES IT
- Our report combines whole genome sequencing with methylation analysis, and highlights conditions where your genetic predisposition and epigenetic activation both point higher.
- It is a tool for informed conversations with professionals, not a diagnosis.
References
- Fraga MF, et al. Epigenetic differences arise during the lifetime of monozygotic twins. PNAS. 2005;102:10604–10609.
- Kuchenbaecker KB, et al. Risks of breast, ovarian, and contralateral breast cancer for BRCA1 and BRCA2 mutation carriers. JAMA. 2017;317:2402–2416.
- Khera AV, et al. Genome-wide polygenic scores for common diseases identify individuals with risk equivalent to monogenic mutations. Nature Genetics. 2018;50:1219–1224.
- Ruby JG, et al. Estimates of the heritability of human longevity are substantially inflated due to assortative mating. Genetics. 2018;210:1109–1124.
- Bird A. Perceptions of epigenetics. Nature. 2007;447:396–398.
See your own genetics and epigenetics
One blood sample: whole genome sequencing, DNA methylation analysis and an estimate of your biological age.
This article is for education and is not medical advice. An estimated biological age is not a clinical diagnosis; please discuss any health decisions with a qualified professional. Prof. Milena Georgieva is Epix AI’s co-founder and Chief Science Officer; videos are credited to their original publishers.