The mutational profile of the yeast genome is shaped by replication.
Mol Biol Evol
; 29(3): 905-13, 2012 Mar.
Article
en En
| MEDLINE
| ID: mdl-22114361
ABSTRACT
Despite the scrutiny that has been directed for years at the yeast genome, relatively little is known about the impact of replication on the substitution dynamics in Saccharomyces cerevisiae. Here, we show that the mutation rate increases with the replication timing by more than 30% between the earliest and the latest replicating regions. In addition, we found a mutational asymmetry associated with the polarity of replication resulting in higher rates of substitutions toward C and A than toward G and T in leading strands (reciprocally more substitutions toward G and T in lagging strands). Such mutational asymmetries applied over long evolutionary periods should generate compositional skews between the two DNA strands. Thus, we show that the leading replicating strands present an excess of C over G and of A over T in the genome of S. cerevisiae (reciprocally an excess of G + T over C + A in lagging strands). We also show that the nucleotide frequencies at mutational equilibrium predict a compositional skew at equilibrium very close to the observed skew between leading and lagging strands, suggesting that compositional equilibrium has been nearly attained in the present day genome of S. cerevisiae. Surprisingly, the direction of this skew is inverted compared with the one in the human genome.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Saccharomyces cerevisiae
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Genoma Fúngico
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Replicación del ADN
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Tasa de Mutación
Idioma:
En
Revista:
Mol Biol Evol
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
2012
Tipo del documento:
Article
País de afiliación:
Francia