Just wondering if there is a way to determine the density of the heterochromatin round-pattern “beads” found in electron micrographs. If there are different types of heterochromatin, then it makes sense that the packing of these distinct types (wikipedia, quoted below – seems to suggest more than the two mentioned in some literature more likely – “a continuum between the two extremes of constitutive and facultative heterochromatin”) will be visible with transmission electron microscopy. So how does one go about making the assessments – in terms of packing of the beads… i only call them beads because i haven’t found what anyone else has named them, and because nature likes to repeat it self when it finds a good solution for a problem (in this case winding up miles and miles of long stringie DNA in such a manner that i has enough order to be accessed for various purposes), and because wrapping around proteins works well… likely it is used more than in one variation.

With TEM, chromatin is found in two distinct configurations, traditionally named euchromatin and heterochromatin based on the density of heavy metal staining of ultrathin sections and this attributed loose and tighter packaging. Heterochromatin is usually localized to the periphery of the nucleus, but also includes centromeres and telomeres and inactivated X-chromosome in females.
If as reported by some, there are 4 or 5 different organizational states to condensed chromatin (probably a couple to euchromatin as well (particularly there are inter chromatin granule clusters right off the bat) there should be a way to measure the different areas — unless they wind with each other in close approximation, then that would be difficult to detect.

I have seen (maybe posted as well) differences in the densities along the inner nuclear membrane, and am wondering if these are related to nuclear pore occurrences, and certainly appear to be related to transcriptional and translational activity. Just thinking out loud. This could relate as well to the number of ribosomes that appear on the outer nuclear membrane in areas justaposed to heterochromatin on the inner nuclear membrane.