'Borgs' are newly discovered (2021) large functional DNA sequences found in the cell nucleus, but outside the chromosomes.

They have been found, in abundance, in some species of the micro-organisms Archaea - in particular, ones which can oxidise and remove methane from the environment. On a global scale, the activities of these organisms are crucial for controlling methane levels (methane being a naturally occurring and powerful 'Greenhouse Gas').

It's speculated that the DNA 'borgs' might be playing an important part in coding for proteins which control the oxidising process.

Borgs are enigmatic extrachromosomal elements that can approach (and likely exceed) 1 Mbp in length We can neither prove that they are archaeal viruses or plasmids or mini-chromosomes, nor can we prove that they are not. Regardless of the name, they are clearly different from anything that has been reported previously. It is fascinating to ponder their possible evolutionary origins. Are they giant linear viruses or plasmids unlike anything previously reported? Alternatively, are they auxiliary chromosomes?

See : Borgs are giant extrachromosomal elements with the potential to augment methane oxidation Bio RXiv, July 2021

Also see : Cellular organellesplugin-autotooltip__plain plugin-autotooltip_bigCellular organelles

Eukaryotic cells are cells which have a nucleus. Within that nucleus are various discrete structures with very specific functions that are, as a group, called 'organelles'.

In the 1970s a book by professor Lynn Margulis (titled Origin of Eukaryotic Cells)