The Association of DNA with Nucleosomes Means That the Default

Question

The association of DNA with nucleosomes means that the default state for eukaryotic genes is to be
A) repressed by silencers.
B) turned on.
C) activated by enhancers.
D) turned off.

Accepted Answer

The association of DNA with nucleosomes generally causes it to be condensed and less accessible to transcription machinery, which means that the default state for eukaryotic genes is to be turned off or not expressed. This default state can be overcome by the action of activators and enhancers that recruit additional transcription factors and modify the local chromatin structure to allow access to the DNA. Conversely, repressors and silencers can reinforce the default state and further limit gene expression. However, without any regulatory inputs, most eukaryotic genes would likely remain in an off state due to nucleosome-mediated repression.