Recombination does not hinder formation or detection of ecological species of Synechococcus inhabiting a hot spring cyanobacterial matFrontiers in Microbiology (2016)
Recent studies of bacterial speciation have claimed to support the biological species concept—that reduced recombination is required for bacterial populations to diverge into species. This conclusion has been reached from the discovery that ecologically distinct clades show lower rates of recombination than that which occurs among closest relatives. However, these previous studies did not attempt to determine whether the more-rapidly recombining close relatives within the clades studied may also have diversiﬁed ecologically, without beneﬁt of sexual isolation. Here we have measured the impact of recombination on ecological diversiﬁcation within and between two ecologically distinct clades (A and B’) of Synechococcus in a hot spring microbial mat in Yellowstone National Park, using a cultivation-free, multi-locus approach. Bacterial artiﬁcial chromosome (BAC) libraries were constructed from mat samples collected at 60◦C and 65◦C. Analysis of multiple linked loci near Synechococcus 16S rRNA genes showed little evidence of recombination between the A and B’ lineages, but a record of recombination was apparent within each lineage. Recombination and mutation rates within each lineage were of similar magnitude, but recombination had a somewhat greater impact on sequence diversity than mutation, as also seen in many other bacteria and archaea. Despite recombination within the A and B’ lineages, there was evidence of ecological diversiﬁcation within each lineage. The algorithm Ecotype Simulation identiﬁed sequence clusters consistent with ecologically distinct populations (ecotypes), and several hypothesized ecotypes were distinct in their habitat associations and in their adaptations to different microenvironments. We conclude that sexual isolation is more likely to follow ecological divergence than to precede it. Thus, an ecology-based model of speciation appears more appropriate than the biological species concept for bacterial and archaeal diversiﬁcation.
- population genetics,
- multi-locus sequence typing,
- Ecotype Simulation,
Publication DateJanuary 14, 2016
Citation InformationMelanie C. Melendrez, Eric D. Becraft, Jason M. Wood, Millie T. Olsen, et al.. "Recombination does not hinder formation or detection of ecological species of Synechococcus inhabiting a hot spring cyanobacterial mat" Frontiers in Microbiology Vol. 6 Iss. 1540 (2016)
Available at: http://works.bepress.com/frederick_cohan/67/