igor b - Academia.edu (original) (raw)
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University of the Basque Country, Euskal Herriko Unibertsitatea
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Papers by igor b
Annual Review of Biochemistry, 1980
IThe US Government has the right to retain a nonexclusive royalty-free license in and to any copy... more IThe US Government has the right to retain a nonexclusive royalty-free license in and to any copyright covering this paper. 2Abbreviations used are bp, base pairs; kb, kilobases; rDNA, ribosomal DNA; pre-rRNA, precursor to ribosomal RNA; NO, nucleolus organizer; Ig, ...
Genome Biology, 2002
Background Gene duplications have a major role in the evolution of new biological functions. Theo... more Background Gene duplications have a major role in the evolution of new biological functions. Theoretical studies often assume that a duplication per se is selectively neutral and that, following a duplication, one of the gene copies is freed from purifying (stabilizing) selection, which creates the potential for evolution of a new function. Results In search of systematic evidence of accelerated evolution after duplication, we used data from 26 bacterial, six archaeal, and seven eukaryotic genomes to compare the mode and strength of selection acting on recently duplicated genes (paralogs) and on similarly diverged, unduplicated orthologous genes in different species. We find that the ratio of nonsynonymous to synonymous substitutions (Kn/Ks) in most paralogous pairs is <<1 and that paralogs typically evolve at similar rates, without significant asymmetry, indicating that both paralogs produced by a duplication are subject to purifying selection. This selection is, however, substantially weaker than the purifying selection affecting unduplicated orthologs that have diverged to the same extent as the analyzed paralogs. Most of the recently duplicated genes appear to be involved in various forms of environmental response; in particular, many of them encode membrane and secreted proteins. Conclusions The results of this analysis indicate that recently duplicated paralogs evolve faster than orthologs with the same level of divergence and similar functions, but apparently do not experience a phase of neutral evolution. We hypothesize that gene duplications that persist in an evolving lineage are beneficial from the time of their origin, due primarily to a protein dosage effect in response to variable environmental conditions; duplications are likely to give rise to new functions at a later phase of their evolution once a higher level of divergence is reached.
Inventiones Mathematicae, 1980
The remarkable link between the structures of mathematics and physics is exemplified by numerous ... more The remarkable link between the structures of mathematics and physics is exemplified by numerous instances in the development of these two disciplines. This link has remained ever mysterious. It comes up in the most unexpected situations and only further developments ...
Annual Review of Biochemistry, 1980
IThe US Government has the right to retain a nonexclusive royalty-free license in and to any copy... more IThe US Government has the right to retain a nonexclusive royalty-free license in and to any copyright covering this paper. 2Abbreviations used are bp, base pairs; kb, kilobases; rDNA, ribosomal DNA; pre-rRNA, precursor to ribosomal RNA; NO, nucleolus organizer; Ig, ...
Genome Biology, 2002
Background Gene duplications have a major role in the evolution of new biological functions. Theo... more Background Gene duplications have a major role in the evolution of new biological functions. Theoretical studies often assume that a duplication per se is selectively neutral and that, following a duplication, one of the gene copies is freed from purifying (stabilizing) selection, which creates the potential for evolution of a new function. Results In search of systematic evidence of accelerated evolution after duplication, we used data from 26 bacterial, six archaeal, and seven eukaryotic genomes to compare the mode and strength of selection acting on recently duplicated genes (paralogs) and on similarly diverged, unduplicated orthologous genes in different species. We find that the ratio of nonsynonymous to synonymous substitutions (Kn/Ks) in most paralogous pairs is <<1 and that paralogs typically evolve at similar rates, without significant asymmetry, indicating that both paralogs produced by a duplication are subject to purifying selection. This selection is, however, substantially weaker than the purifying selection affecting unduplicated orthologs that have diverged to the same extent as the analyzed paralogs. Most of the recently duplicated genes appear to be involved in various forms of environmental response; in particular, many of them encode membrane and secreted proteins. Conclusions The results of this analysis indicate that recently duplicated paralogs evolve faster than orthologs with the same level of divergence and similar functions, but apparently do not experience a phase of neutral evolution. We hypothesize that gene duplications that persist in an evolving lineage are beneficial from the time of their origin, due primarily to a protein dosage effect in response to variable environmental conditions; duplications are likely to give rise to new functions at a later phase of their evolution once a higher level of divergence is reached.
Inventiones Mathematicae, 1980
The remarkable link between the structures of mathematics and physics is exemplified by numerous ... more The remarkable link between the structures of mathematics and physics is exemplified by numerous instances in the development of these two disciplines. This link has remained ever mysterious. It comes up in the most unexpected situations and only further developments ...