Negative frequency-dependent selection is intensified at higher population densities in protist populations.
Negative frequency-dependent selection is intensified at higher population densities in protist populations.
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DOI：
10.1098/rsbl.2015.0192
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发表时间：
2015-06
期刊：
影响因子：
3.3
通讯作者：
Brockhurst MA
中科院分区：
文献类型：
--
作者：
Minter EJ;Watts PC;Lowe CD;Brockhurst MA
自由生活的原生生物的自然种群通常表现出高水平的种内多样性，但这令人费解，因为经典进化理论预测具有高适应性的基因型占主导地位，特别是在选择有效的大种群中。在这里，我们通过多对菌株之间的竞争实验来测试负频率依赖性选择（NFDS）是否在维持海洋鞭毛虫 Oxyrris 码头的多样性中发挥作用。我们观察到菌株对频率和密度的特异性反应，但 NFDS 的总体特征在种群密度较高时会增强。因为我们的菌株不是根据预期表现出 NFDS 的特定性状先验选择的，所以这些数据代表了对 NFDS 在维持原生生物种群多样性方面的作用的相对公正的估计。这些发现可能有助于解释周期性达到异常高种群密度的水华形成浮游生物如何保持大量的种内多样性。
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.