ISSN:
1432-1432
Keywords:
Ornithine decarboxylase
;
mRNA evolution
;
Episodic evolution
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Ornithine decarboxylase (ODC) is the first enzyme in the polyamine biosynthetic pathway. We have studied the evolutionary history of the mammalian ODC mRNA, focusing on the rate of accumulation of sequence divergence within specific subregions of the molecule. The phylogenetic relationships among the mRNAs from several mammalian species, including two mouse species, rat, hamster, and human, were determined based upon the numbers of synonymous substitutions in pair-wise comparisons of mRNA coding regions. The separation times for the mRNAs were very similar to those for the corresponding species, suggesting that ODC is encoded by orthologous genes in the different species. Analysis of divergence patterns in four subregions, or domains, of the mRNA (the 5′untranslated region, the coding region, and two domains of the 3′-untranslated region) showed that the domains have evolved in a noncoordinate fashion. Furthermore, evolution of each subregion has been episodic, with periods of both rapid and slow sequence divergence. We suggest that the episodic pattern of ODC mRNA evolution may indicate the existence of selection pressures that were exerted in a time- and domain-specific manner during mammalian speciation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00556360
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