heterochromatin
/ˌhɛtəroʊˈkroʊmətɪn/
noun
- A tightly packed form of DNA in the cell nucleus that is usually inactive and not used to make proteins.
- Scientists discovered that heterochromatin helps keep certain genes turned off.
- Heterochromatin appears as dark spots under a microscope because it is so densely packed.
- Changes in heterochromatin can affect how cells age and function.