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Epigenetics: same DNA sequence, different activity
Make it clearer
Epigenetics studies something that sounds at first like a contradiction: genes can be used a different way without the DNA changing a single letter. The sequence, meaning the order those letters are written in, stays exactly the same. What changes is which genes get used and which ones go unused.
That happens through chemical marks laid on top. One is DNA methylation; others are histone modifications. Depending on how they're placed, those marks make certain genes easier or harder to use. That's why two different kinds of cells can carry the same DNA inside and still use different genes: it's the same book, with tabs stuck on different pages. And the tabs aren't stuck there for good, they can change during development or over the course of a life.
In brief
Epigenetics studies changes in how genes are used that do not alter the DNA sequence itself.
The DNA letters remain the same; what changes is which regions are more or less available for the cell to use.
DNA methylation and histone modifications are chemical marks that can make certain genes easier or harder for a cell to use.
This helps explain how two cell types can share the same DNA yet use different genes. These marks can also change during development or over a lifetime.
Sources (2)
- National Human Genome Research InstituteEpigenomics Fact Sheet
- National Human Genome Research InstituteEpigenetics
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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