skip to main content


Title: Recombination Does Not Hinder Formation or Detection of Ecological Species of Synechococcus Inhabiting a Hot Spring Cyanobacterial Mat

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’more » 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.« less
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1]
  1. Montana State Univ., Bozeman, MT (United States)
  2. Pennsylvania State Univ., University Park, PA (United States)
  3. Univ. of Southern California, Los Angeles, CA (United States)
  4. J. Craig Venter Inst., Rockville, MD (United States)
  5. Wesleyan Univ., Middletown, CT (United States)
Publication Date:
Grant/Contract Number:
EF-0328698; NAG5-8807; NX09AM87G; 112443; 911352
Accepted Manuscript
Journal Name:
Frontiers in Microbiology
Additional Journal Information:
Journal Volume: 6; Journal ID: ISSN 1664-302X
Frontiers Research Foundation
Research Org:
Montana State Univ., Bozeman, MT (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; population genetics; speciation; Synechococcus; cyanobacteria; multi-locus sequence typing; Ecotype Simulation; ecotype; recombination
OSTI Identifier: