ther isn't much room for some in between sort of common ancestor.
I wasn't thinking of 'in-between' when I was thinking of common
ancestor, rather more like enabling the development of either --
which really isn't the same -- honest
Why do you think your scenario is any less of a 'conundrum'
I was thinking more scope for changes to become manifest in
smaller steps ... in reference to this DNA structure comment
someone raised.
the prokaryotes precede the eukaryotes by a couple of billion years
So by 'more primitive' you just meant older?