Woese's progenote hypothesis

The types of phenotypic changes that accompanied the
formation of the three primary kingdoms are of a special
nature. General differences in cell architecture among the
three groups are remarkable, as are their differences in
intermediary metabolism, and each kingdom seems to have
its own unique version of every fundamental cellular function:
translation, transcription, genome replication and control,
and so on. The kind of variation that subsequently
occurred within each of the kingdoms is minor by comparison.
Thus the mode of evolution accompanying the transition
from the universal ancestor is unusual; far more novelty
arose during formation of the primary kingdoms than during
the subsequent evolutionary course in any one of them.
It is hard to avoid concluding that the universal ancestor
was a very different entity than its descendants. If it were a
more rudimentary sort of organism, then the tempo of its
evolution would have been high and the mode of its evolution
highly varied, greatly expanded.
Were the actual root of the universal tree (Fig. 4) located
in the vicinity of the deepest branchings in any one of the
three primary kingdoms, the above argument concerning
sequence distances would not apply to that kingdom, which
makes it conceivable that the universal ancestor had the
basic phenotype of that group. (This argument is particularly
attractive as regards the archaebacteria, for the group sits
relatively close to the intersection of the three primary
lineages; see Fig. 4.) However, this would still leave the
problem of deriving the other two phenotypes from a third
comparably complex one, which entails drastic changes at
the molecular level in most functions in the cell. In my
opinion the changes in overall cell structure, organization,
etc., required to change one of the three phenotypes into
either of the others are too drastic and disruptive to have
actually occurred.
Accepting all this, the only solution to the problem is for
the universal ancestor to have been a progenote.

In my opinion the changes in overall cell structure, organization, etc., required to change one of the three phenotypes into either of the others are too drastic and disruptive to have
actually occurred.

The progenote is a theoretical construct, an entity that, by definition, has a rudimentary, imprecise linkage between its genootype and phenotype (251, 256). (Extant organisms, which have precise, accurate links between genotype and phenotype, are then genotes.) The certainty that progenotes existed at some early stage in evolution follows from the nature of the translation apparatus.

In other words, he cannot see anyway that is feasible or reasonable for a common ancestor to evolve into what he classifies as the 3 primary kingdoms, at least if their shape and characteristics are handed down by their genes and so mutations are selected via natural selection and so the creatures' features evolve via gradual change into different creatures. This is important. He says the changes "are too drastic and disruptive to have
actually occurred."

So Woese recognizes that there is a serious problem claiming that the "three kingdoms" as having evolved by observable processes that we know of today. He posits a non-observed theoritical construct as a solution.

But there are problems. If there is "imprecise linkage between phenotype and genotype", then how is natural selection suppossed to work? If an organism has a beneficial trait, that trait won't necessarily be passed on and so the fact that organism survives does not mean it's progeny is more likely to.

Furthermore, isn't the claim that natural selection can work with the precursor, the hypothetical (mythical?) RNA-based duplicators, of the progenote (another imagined construct).

Maybe the truth is simply that the 3 primary kingdoms Woese defines did not evolve from a common ancestor at all?

sorry but you are trying to attack his paper based on red herrings

i'm not sure where you get this idea that he is saying its a problem, he says no such thing, are you even reading the whole thing or just skimming it? the gist of what he is saying is it would have to have features of all three kingdoms

explain to me what that has to do with NS

Genes would then be disjoint, and they could have existed in high copy
numbers, in whic h case an appropriately simple mechanism
can be imagined that would detect errors in individual genes
and selectively eliminate (not correct) the flawed o nes (251).

Within a decade we will have before us at least an order of magnitude more evolutionary information than we now possess and will be able to infer a great deal more with a great deal more assurrance than we now can.

This is a clear example of taking a quote out of context.

In principle the universal ancestor could have resembled
any one of the three major types of extant organisms. It also
could have in essence been a collage of all three, or have
been very unlike any of them. I will argue that the last
alternative is the correct one and that the universal ancestor
was a progenote.

Woese refers only to one of the three Kingdoms evolving from another.

In my opinion the changes in overall cell structure, organization,etc., required to change one of the three phenotypes into either of the others are too drastic and disruptive to have
actually occurred.
Accepting all this, the only solution to the problem is for
the universal ancestor to have been a progenote.

far more novelty arose during formation of the primary kingdoms than during the subsequent evolutionary course in any one of them.

Accordingly Woese proposes that all three Kingdoms evolved from a significantly simpler ancestor.

the universal ancestor could have resembled
any one of the three major types of extant organisms. It also
could have in essence been a collage of all three,