K-r/K-c but not d(N)/d(S) correlates positively with body mass in birds, raising implications for inferring lineage-specific selection

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Etat: Public
Version: Final published version
ID Serval
serval:BIB_DC967BE5088F
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
K-r/K-c but not d(N)/d(S) correlates positively with body mass in birds, raising implications for inferring lineage-specific selection
Périodique
Genome Biology
Auteur(s)
Weber C.C., Nabholz B., Romiguier J., Ellegren H.
ISSN
1474-760X (electronic)
ISSN-L
1465-6906
Statut éditorial
Publié
Date de publication
2014
Volume
15
Numéro
12
Pages
542
Langue
anglais
Résumé
Background: The ratio of the rates of non-synonymous and synonymous substitution (d(N)/d(S)) is commonly used to estimate selection in coding sequences. It is often suggested that, all else being equal, d(N)/d(S) should be lower in populations with large effective size (Ne) due to increased efficacy of purifying selection. As N-e is difficult to measure directly, life history traits such as body mass, which is typically negatively associated with population size, have commonly been used as proxies in empirical tests of this hypothesis. However, evidence of whether the expected positive correlation between body mass and d(N)/d(S) is consistently observed is conflicting.
Results: Employing whole genome sequence data from 48 avian species, we assess the relationship between rates of molecular evolution and life history in birds. We find a negative correlation between dN/dS and body mass, contrary to nearly neutral expectation. This raises the question whether the correlation might be a method artefact. We therefore in turn consider non-stationary base composition, divergence time and saturation as possible explanations, but find no clear patterns. However, in striking contrast to d(N)/d(S), the ratio of radical to conservative amino acid substitutions (K-r/K-c) correlates positively with body mass.
Conclusions: Our results in principle accord with the notion that non-synonymous substitutions causing radical amino acid changes are more efficiently removed by selection in large populations, consistent with nearly neutral theory. These findings have implications for the use of d(N)/d(S) and suggest that caution is warranted when drawing conclusions about lineage-specific modes of protein evolution using this metric.
Web of science
Open Access
Oui
Création de la notice
15/01/2015 10:57
Dernière modification de la notice
20/08/2019 17:01
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