JTW's Evolutionary Origins - Author: Wachtershauser, Gunter
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Diagnostic Criteria for Pathway Retrodiction
"The most difficult problem of biochemical phylogeny is concerned with the elucidation of patterns of evolutionary changes, E5 to E11. They frequently change not only the catalyst of a pathway, but also the very constitution of the pathway itself. This problem can be subdivided into the diagnostic problem of identifying those extant pathways that underwent extensive evolutionary changes and the problem of reconstruction of the actual course of pathway evolution.
For the diagnostic problem, a number of diagnostic criteria can be established. Extant pathways can be checked whether they satisfy a number of these criteria."
Diagnostic Criteria #1
[pp. 124]
The intermediates in a pathway have no recognizable function other than
the function of being intermediates in this very pathway.
Diagnostic Criteria #2
[pp. 124]
The product of a pathway is involved as a catalyst for an earlier step
in this very same pathway
(e.g. THF in the purine pathway).
Diagnositic Criteria #3
[pp. 124]
A pathway to which (tenatively) accepted historic relations assign an early arrival
requires a catalyst,
to which the historic relations assign a late arrival.
Diagnostic Criteria #4
[pp. 124]
The front section of a pathway consists of constituents
to which the historic relations assign a lated arrival
(e.g. non-surface bonders)
compared to archaic constituents
(e.g. surface bonders)
of the rear section of the same pathway.
Diagnostic Criteria #5
[pp. 124]
The overall pathway is older, as judged by the historic relations,
than some endergonic steps with energy coupling within it.
- Wachtershauser, Gunter
- Groundworks for an Evolutionary Biochemistry: The Iron-Sulphur World
- Progress in Biophysics and Molecular Biology: Vol. 58, No. 2, pp.85-202
- 1992
- [Pubmed]
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