Arlin wonders why research articles frequenly appear in which the
most common ancestor is called "the progenote". The simplest answer
is that people use "progenote" when they mean "progenitor". This is
a problem with command of the English language, not a scientific problem.
As for formally rejecting the proenote hypothesis, Arlin first asks
"Hasn't enough evidence accumulated...?", then cites not evidence,
but an ARGUMENT that existence of homologous DNA-polymearases with
proofreading functions "rules out the possibility". Let us not
confuse evidence with one person's interpretation of some data.
The argument may be persuasive to some, but "rules out the possibility"
is such a strong statement that I would surely require more than
one line of evidence to be persuaded. I might be willing to accept
"Given our current assumptions and understanding the findings concerning
homologous modern DNA polymerases makes the progenote hypothesis seem
unlikely", but that is about as far as I would be willing to go.