Review: mitochondrial chromosomes

[cmungall]

currently these go directly under 'chromosome':

they should be inferred to be under 'mitochondrial chromosome' when GO axioms added, but should we just infer in advance

question (more for GO?)

Which of these:

1. chromosome DisjointUnion autosome OR sex-chromosome; (entailment: mtChrom is-a autosome)
2. chromosome DisjointUnion autosome OR sex-chromosome OR mt chromosome OR chlorplast chromosome

I think 2 seems more sane

[sabrinatoro]

@cmungall
I think the 2nd option is the correct one. Based on what I have found, the organelle chromosomes (i.e mitochondrial and chloroplast chromosomes) are distinct from the autosomes and gnonosomes (sex-chromosomes).

Note book summary: organelle chromosomes:

• appear to be fundamentally circular
• overall organization is not in the highly condensed form
• are present in many copies per cell.
• packaged into nucleoids, which are DNA–protein assemblies composed of mtDNA surrounded by core and peripheral nucleoid factors****

**** this would match the definition of ‘chromosome’ (GO:0005694, A structure composed of a very long molecule of DNA and associated proteins (e.g. histones) that carries hereditary information.), except the definition refers to “a very long molecule of DNA” In human, mitochondrial chromosomes are ~16.5 Kb. Is that ‘very long’?