(
2005-01-04)
Thompson, Janelle R.; Pacocha, Sarah E.; Pharino, Chanathip; Klepac-Ceraj, Vanja; Hunt, Dana E.; Benoit, Jennifer; Sarma-Rupavtarm, Ramahi; Distel, Daniel L.; Polz, Martin F.
The genomic diversity and relative importance of unique genotypes within natural
bacterial populations has remained largely unknown. Here, we analyze the diversity
and annual dynamics of a group of coastal bacterioplankton (>99% 16S rRNA
identity to Vibrio splendidus). We show that this group consists of at least a thousand
distinct genotypes, each occurring at extremely low environmental concentrations
(on average <1 cell/ml). Overall, the genomes show extensive allelic diversity and
size variation. Individual genotypes rarely recurred in samples and allelic
distribution did not show spatial or temporal substructure. Ecological
considerations suggest that much genotypic and possibly phenotypic variation
within natural populations should be considered neutral.
