> As it implies the close spacing is for some kind of mechanical/electrical mechanism within the core of every cell’s nucelus. It is interesting, but not for t

> As it implies the close spacing is for some kind of mechanical/electrical mechanism within the core of every cell’s nucelus. It is interesting, but not for the reasons you may be imagining. And not a mysterious electrical mechanism. It's well-known in the field that (e.g., in humans), chromosomes fold in on themselves in structured ways [1,2]. The functional consequence is not precisely mechanical or electrical -- rather, these folds bring regulatory domains close in 3D space to the sequences which they regulate (which may be far in 1-D sequence distance). These can be elements like "enhancers", which increase the level of transcription (DNA->RNA copying, the first step of gene expression); "insulators", which break up coherent blocks of gene regulation, etc. One of the mediating mechanisms is that regulatory proteins bind to these particular sequences; bringing them together in 3D space allows the assembly of a protein complex that actually carries out the relevant process (eg, transcription). So, what's interesting here? There is extensive evidence of these contacts within mammalian chromosomes, but limited evidence _between_ different chromosomes. Insofar as the paper shows that mammalian macrochromosomes have homology to multiple reptile/avian microchromosomes (really, to their most recent common ancestor), it may be (speculation alert) that intra-chromosome contacts recapitulate contacts and organization seen in the ancestral microchromosomes. (There are also "simple" interactions like wrapping of DNA on protein complexes called nucleosomes, like string on beads, but that's less interesting in this context.) [1] https://en.wikipedia.org/wiki/Nuclear_organization#DNA_looping https://en.wikipedia.org/wiki/Nuclear_organization#DNA_loopi... [2] https://en.wikipedia.org/wiki/Nuclear_organization#Chromosomal_domains https://en.wikipedia.org/wiki/Nuclear_organization#Chromosom...