Molecular Biology and Evolution, Vol 4, 504-513, Copyright © 1987 by Society for Molecular Biology and Evolution
S Yokoyama and R Yokoyama
Phylogenetic relationship and the rates of evolution of mammalian alcohol
dehydrogenases (ADHs) have been studied by using the amino acid sequences
from the human (ADH alpha, ADH beta, and ADH gamma), rat, mouse, and horse
(ADH E and ADH S). With the maize ADH1 and ADH2 used as references, the
patterns of the amino acid replacements in the beta- sheets, alpha-helices,
and random coils in each of the catalytic and coenzyme-binding domains were
analyzed separately. The phylogenetic trees based on the different sets of
amino acid substitutions consistently showed that (1) multiple ADHs in
human and horse have arisen after mammalian radiation, (2) the common
ancestor of human ADHs alpha and beta diverged from the ancestor of ADH
gamma first and the former two ADHs diverged from each other more recently,
and (3) the human ADHs are more closely related to the rodent ADHs than to
the horse ADHs. Furthermore, the estimated branch lengths showed that the
rodent ADHs are evolving faster than the other ADHs. This difference in
evolutionary rate between the two groups of organisms is explainable either
in terms of the difference in the number of cell generations per year or in
terms of reduction of functional constraints.
ORIGINAL ARTICLE
Molecular evolution of mammalian class I alcohol dehydrogenase
Department of Psychiatry, Washington University.
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