This is the sort of long-form comment that I'd write and love to read, signed in just to upvote it, well-put! Nit: chromosomes mostly don't look like little X-

This is the sort of long-form comment that I'd write and love to read, signed in just to upvote it, well-put! Nit: chromosomes mostly don't look like little X-shapes except during cell division, which was historically a useful time to image them (I think because the dye couldn't get through the cell-nucleus wall but during cell division it has dissolved?). But then you are seeing _two_ chromosomes that happen to be bound at a centromere before that centromere gets torn into two by the cytoskeleton dividing the cell in half.