Negative frequency-dependent selection is intensified at higher population densities in protist populations

This is the final version of the article. Available from the Royal Society via the DOI in this record. Natural populations of free-living protists often exhibit high-levels of intraspecific diversity, yet this is puzzling as classic evolutionary theory predicts dominance by genotypes with high fitne...

Full description

Bibliographic Details
Published in:Biology Letters
Main Authors: Minter, EJA, Watts, PC, Lowe, CD, Brockhurst, MA
Format: Article in Journal/Newspaper
Language:English
Published: Royal Society 2015
Subjects:
density dependence
diversity
frequency dependence
plankton
selection
Dinoflagellida
Genetic Variation
Population Density
Genetic
Ocean acidification
Online Access:http://hdl.handle.net/10871/26373
https://doi.org/10.1098/rsbl.2015.0192
Description
Summary:This is the final version of the article. Available from the Royal Society via the DOI in this record. Natural populations of free-living protists often exhibit high-levels of intraspecific diversity, yet this is puzzling as classic evolutionary theory predicts dominance by genotypes with high fitness, particularly in large populations where selection is efficient. Here, we test whether negative frequency-dependent selection (NFDS) plays a role in the maintenance of diversity in the marine flagellate Oxyrrhis marina using competition experiments between multiple pairs of strains. We observed strain-specific responses to frequency and density, but an overall signature of NFDS that was intensified at higher population densities. Because our strains were not selected a priori on the basis of particular traits expected to exhibit NFDS, these data represent a relatively unbiased estimate of the role for NFDS in maintaining diversity in protist populations. These findings could help to explain how bloom-forming plankton, which periodically achieve exceptionally high population densities, maintain substantial intraspecific diversity. E.J.A.M. was supported by a NERC research studentship (NE/H025472/2) as part of the UK Ocean Acidification Research Programme.

Similar Items