Summary
Heritable changes in gene activity, through DNA methylation and histone modification, without altering the DNA sequence.
In depth
Mechanisms include DNA methylation, histone modification and non-coding RNAs. Marks can be influenced by diet, stress and toxins, and some are inherited through cell division. The Dutch Hunger Winter study linked prenatal famine to later health outcomes.
Epigenetic changes are reversible, unlike mutations.
DNA methylation commonly occurs at CpG sites and silences genes, while histone acetylation opens chromatin. The enzymes involved can be reversed, which makes epigenetic drugs possible, such as azacitidine for myelodysplastic syndrome. Identical twins diverge in methylation patterns as they age, which can explain differences in disease.
The Dutch Hunger Winter (1944 to 1945) showed that babies conceived during famine had higher rates of obesity and heart disease and altered methylation decades later. In honeybees, royal jelly alters methylation so that larvae develop into queens rather than workers, with the same genome.
Remember: epigenetic changes do not alter the DNA sequence, they are marks that affect how it is read, and many are reset between generations.
Frequently asked questions
What is Epigenetics?
Heritable changes in gene activity, through DNA methylation and histone modification, without altering the DNA sequence.
Which area of biology covers Epigenetics, and how advanced is it?
Epigenetics is one of the 54 topics in Genetics. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Heredity, Genomic Imprinting, Point Mutations.
Can you give an example of Epigenetics?
Identical twins show growing epigenetic differences with age.
What should I learn before Epigenetics?
Work through the Beginner topics in Genetics first, such as Heredity, Gene, Allele, then return to Epigenetics. Advanced topics assume the Intermediate vocabulary.
What topics are related to Epigenetics?
The closest topics to Epigenetics are Heredity, Genomic Imprinting, Point Mutations, Down Syndrome. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Epigenetics?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Epigenetics. To practise the whole of Genetics, use the Genetics quiz.
How is Epigenetics different from Heredity?
Epigenetics: Heritable changes in gene activity, through DNA methylation and histone modification, without altering the DNA sequence. Heredity: The passing of traits from parents to offspring through genetic material. Read both side by side and note what each one explains.
How should I study Epigenetics step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Heredity and explain the difference aloud. Finally, take the Genetics quiz and come back to this page for any question you miss.