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THE DYNAMICS OF DIVERSIFICATION IN EVOLVING PSEUDOMONAS POPULATIONS
Author(s) -
Barrett Rowan D. H.,
Bell Graham
Publication year - 2006
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.0014-3820.2006.tb01130.x
Subject(s) - biology , diversification (marketing strategy) , evolutionary biology , marketing , business
Determining the mechanisms that promote the evolution of diversity is a central problem in evolutionary biology. Previous studies have demonstrated that diversification occurs in complex environments and that genotypes specialized on alternative resources can be maintained over short time scales. Here, we describe a selection experiment that has tracked the dynamics of adaptive diversification within selection lines of the asexual becteria Pseudomonas flurescens over about 900 generations. We cultured experimental populatins from the same two isogenic ancestral strains in simple, single‐substrate environments or in complex, four‐substrate envoronments. Follwoing selection we assayed the growth of genotypes from each population on each substrate individually. We estimated multational heritability, V m /V e , 1 × 10 ‐3 per generation in simple envoronments and 3 × 10 ‐3 per generation in complex envoronemtns. These values are roughly consistent with estimates repotted in other systems. Populatins selected in complex environments evolved into genetically diverse communities. Genotypes exhibited greater metabolic differentition from other genotypes in their own population than to genotypes evolving in other populations, presumbaly as a result of resource competition. In populations selected in simple enviornments, little genetic diversity evolved, and genotypes shared very similar phenotypes. Our findings suggest that ecological opportunity providedby envoronmental complexity plays a major role in the evolution and maintenance of diversity.