Single-amino acid variants reveal evolutionary processes that shape the biogeography of a global SAR11 subclade.

ABSTRACT: Members of the SAR11 order Pelagibacterales dominate the surface oceans. Their extensive diversity challenges emerging operational boundaries defined for microbial 'species' and complicates efforts of population genetics to study their evolution. Here, we employed single-amino acid variants (SAAVs) to investigate ecological and evolutionary forces that maintain the genomic heterogeneity within ubiquitous SAR11 populations we accessed through metagenomic read recruitment using a single isolate genome. Integrating amino acid and protein biochemistry with metagenomics revealed that systematic purifying selection against deleterious variants governs non-synonymous variation among very closely related populations of SAR11. SAAVs partitioned metagenomes into two main groups matching large-scale

SUBMITTER: Delmont TO 

PROVIDER: S-EPMC6721796 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature