Genetics vs Epigenetics: What Is the Difference?

The simplest way to understand genetics vs epigenetics is to separate the DNA sequence itself from the biological processes that influence how that DNA is used.

Genes vs Environment: Why DNA Does Not Determine Everything

The familiar idea of genes vs environment is really an interaction rather than a competition. Your genes influence susceptibility, while environment and biochemistry influence how that susceptibility is expressed.

Two people can carry similar genetic variants yet develop very different symptoms, laboratory abnormalities and health outcomes.

Important influences on gene expression and environment include:

What Is Epigenetics?

Epigenetics refers to regulatory processes that influence gene activity without changing the underlying DNA sequence.

DNA methylation is one important epigenetic mechanism. Other mechanisms include histone modification, chromatin organization and regulatory RNA activity.

This is why inherited genetics vs gene expression should not be treated as the same thing. Carrying a genetic variant does not automatically tell us how strongly that pathway is being expressed or whether it is currently producing a clinically important biochemical abnormality.

Genetic Testing Limitations: Risk Is Not the Same as Current Function

Genetic testing can be extremely valuable. But one of the most important genetic testing limitations is that a DNA result often identifies susceptibility rather than current physiology.

A common SNP may suggest that an enzyme could function differently, but the genetic result alone may not answer:

• Is the predicted pathway actually impaired now?
• Is the gene variant being expressed in a clinically important way?
• Has another metabolic pathway compensated?
• Are symptoms actually related to the variant?
• Is the predicted biochemical abnormality measurable?
• Has nutrition or environment changed the phenotype?
• Would treatment directed only at the SNP improve the problem?

When Genetic Testing Can Be Diagnostic

The limitations of genetic testing should not be confused with saying that genetic testing is unimportant. In the right setting, it can be highly informative or diagnostic.

The distinction becomes particularly important when common SNP reports are used to explain complex conditions such as depression, anxiety, fatigue, cognitive decline, inflammation, mitochondrial dysfunction or impaired methylation.

Epigenetic Testing vs Functional Biochemical Testing

Epigenetic testing and functional biochemical testing are related concepts, but they are not interchangeable.

True epigenetic testing may examine regulatory features such as DNA methylation patterns. By contrast, tests such as SAM, SAH, CoQ10, lactate, pyruvate, acylcarnitines, magnesium, cystatin C, amino acids, 8-OHdG and lipid peroxides measure current biochemical or physiologic function.

Those functional tests do not directly measure the epigenome. They can, however, help characterize the metabolic environment in which gene expression is occurring.

Genetic Testing vs Functional Testing: Two Different Questions

Once the difference between genetics and epigenetics is clear, functional testing becomes easier to understand.

Genetic testing asks what biological vulnerabilities you inherited. Functional testing asks what is actually happening in the body now.

Type of Information	What It Can Tell You
Genetic testing	Inherited variants, mutations, susceptibility and pharmacogenomic information
Epigenetic testing	Selected regulatory changes affecting gene activity, depending on the test used
Functional biochemical testing	Current metabolites, nutrients, oxidative stress, mitochondrial function, mineral status, methylation-related metabolites and other physiology

MTHFR Testing Limitations: A Classic Genetics vs Epigenetics Example

MTHFR is one of the clearest examples of why genetics vs epigenetics matters clinically.

An MTHFR genetic variant can indicate inherited potential for altered folate metabolism. It does not directly measure methylation status, DNA methylation or current methylation capacity.

These are important MTHFR testing limitations. A genotype predicts potential; it does not provide a direct measurement of the methylation cycle.

The more useful biochemical questions may include:

• What is your SAM?
• What is your SAH?
• What is the SAM:SAH relationship?
• What is your methionine?
• What is your homocysteine?
• Is folate actually deficient?
• Is vitamin B12 adequate?
• Is mitochondrial ATP production adequate?
• Are there biochemical factors increasing methylation demand?

Two people can carry the same MTHFR variant and have very different biochemical findings.

MTHFR Testing Limitations in Mental Health Methylation Testing

Methylation Testing: Measuring Function Instead of Predicting It

Methylation testing can provide current biochemical information that cannot be determined from an MTHFR SNP alone.

Important methylation-related markers include:

• SAM — a principal biological methyl donor
• SAH — an inhibitor of methyltransferase reactions
• SAM:SAH relationship — useful for assessing methylation potential
• Methionine — precursor for SAM synthesis
• Homocysteine — central to methylation and transsulfuration metabolism

These measurements address a fundamentally different question from genetic testing:

This distinction is particularly important when an MTHFR result is being used to make assumptions about current methylation status.

View Methylation Testing