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Comparing effective population sizes of dominant marine alphaproteobacteria lineages
Author(s) -
Luo Haiwei,
Swan Brandon K.,
Stepanauskas Ramunas,
Hughes Austin L.,
Moran Mary Ann
Publication year - 2014
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12129
Subject(s) - roseobacter , biology , nonsynonymous substitution , lineage (genetic) , alphaproteobacteria , population , context (archaeology) , ecology , adaptation (eye) , evolutionary biology , population size , phylogenetics , bacteria , genetics , clade , gene , 16s ribosomal rna , paleontology , demography , genome , neuroscience , sociology
Summary A fundamental question in marine microbial ecology is how microbes adapt to ocean environments. Although numerically dominant populations are typically considered more successful, higher census population sizes (N c ) do not equate directly to a greater capability for adaptation. Instead, effective population size (N e ) determines the fate of deleterious and favourable mutations, and thus is a key parameter for determining the adaptive potential of a population. In the case of the SAR11 and Roseobacter lineages, two abundant heterotrophic bacteria in ocean surface waters with contrasting life history strategies, culture‐independent population surveys suggest that SAR11s have greater N c than Roseobacters. To determine relative N e , we compared the ratio of nonsynonymous to synonymous substitution rates (ω) of recently diverged lineages of these taxa. Values of ω associated with several of the Roseobacter subclades were lower than for SAR11 subclades, suggesting greater N e in these cases. Most Roseobacter lineages also had smaller ω values compared with an atypical basal Roseobacter lineage with a large N c . This finding provides insight into variability in N e across two important marine bacterial lineages, and provides an evolutionary context for considering how heterotrophic marine bacteria may differ in their ability to adapt to changing ocean habitats.