Chromomere

A chromomere, also known as an idiomere, is one of the serially aligned beads or granules of a eukaryotic chromosome, resulting from local coiling of a continuous DNA thread.

In areas of chromatin with the absence of transcription, condensing of DNA and protein complexes will result in the formation of chromomeres.

These chromosomes consist of more than 1000 copies of the same chromatid that are aligned and produce alternating dark and light bands when stained.

The extra acetylation loosens chromatin from a condensed form, making it more accessible to proteins involved in transcription.

[2][5] The two sister chromatids of a lampbrush chromosome separate fully, forming lateral loops that extend from chromomeres, and act as transcription complexes.

These regions of chromatin that have not been transcribed are located at the ends of the loops that were formed by the sister chromatids of a lampbrush chromosome.

[2] Each chromomere can have up to several pairs of loops from lampbrush chromosomes originating from it, as well as micro-loops that cannot be detected with a light microscope.

Chromatin within the chromomere are held in position by a variety of histone modifications and epigenetic markers.