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Titolo:
Synonymous rates at the RpII215 gene of Drosophila: Variation among species and across the coding region
Autore:
Llopart, A; Aguade, M;
Indirizzi:
Univ Barcelona, Fac Biol, Dept Genet, Barcelona 08071, Spain Univ Barcelona Barcelona Spain 08071 Dept Genet, Barcelona 08071, Spain
Titolo Testata:
GENETICS
fascicolo: 1, volume: 152, anno: 1999,
pagine: 269 - 280
SICI:
0016-6731(199905)152:1<269:SRATRG>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
RNA-POLYMERASE-II; CODON USAGE BIAS; CARBOXYL-TERMINAL DOMAIN; OBSCURA GROUP; MOLECULAR EVOLUTION; NATURAL-SELECTION; LARGEST SUBUNIT; NONSYNONYMOUS SUBSTITUTIONS; SACCHAROMYCES-CEREVISIAE; GENERATION-TIME;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
71
Recensione:
Indirizzi per estratti:
Indirizzo: Llopart, A Univinarcelona, Fac Biol, Dept Genet, Av Diagonal 645, Barcelona 08071, Spa Univ Barcelona Av Diagonal 645 Barcelona Spain 08071 8071, Spa
Citazione:
A. Llopart e M. Aguade, "Synonymous rates at the RpII215 gene of Drosophila: Variation among species and across the coding region", GENETICS, 152(1), 1999, pp. 269-280

Abstract

The region encompassing the RpII215 gene that encodes the largest component of the RNA polymerase II complex (1889 amino acids) has been sequenced inDrosophila subobscura, D. madeirensis, D. guanche, and D. pseudoobscura. Nonsynonymous divergence estimates (K-a) indicate that this gene has a very low rate of amino acid replacements. Given its low K-a and constitutive expression, synonymous substitution rates are, however, unexpectedly high. Sequence comparisons have allowed the molecular clock hypothesis to be tested. D. guanche is an insular species and it is therefore expected to have a reduced effective size relative to D. subobscura. The significantly higher rate of synonymous substitutions detected in the D. guanche lineage could be explained if synonymous mutations behave as nearly neutral. Significant departure from the molecular clock hypothesis for synonymous and nonsynonymoussubstitutions was detected when comparing the D. subobscura, D. pseudoobscura, and D. melanogaster lineages. Codon bias and synonymous divergence between D. subobscura and D. melanogaster were negatively correlated across the RpII215 coding region, which indicates that selection coefficients for synonymous mutations vary across the gene. The C-terminal domain (CTD) of theRpII215 protein is structurally and functionally differentiated from the rest of the protein. Synonymous substitution rates were significantly different in both regions, which strongly indicates that synonymous mutations in the CTD and in the non-CTD regions are under detectably different selectioncoefficients.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 13:00:04