Evolution, Ecology and Behaviour, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom.
Proc Natl Acad Sci U S A. 2012 Dec 18;109(51):20998-1003. doi: 10.1073/pnas.1214398110. Epub 2012 Dec 3.
The mechanisms that underpin the varied spatial genetic structures exhibited by free-living marine microorganisms remain controversial, with most studies emphasizing a high dispersal capability that should redistribute genetic diversity in contrast to most macroorganisms whose populations often retain a genetic signature of demographic response to historic climate fluctuations. We quantified the European phylogeographic structure of the marine flagellate Oxyrrhis marina and found a marked difference in spatial genetic structure, population demography, and genetic diversity between the northwest Atlantic and Mediterranean Sea that reflects the persistent separation of these regions as well as context-dependent population responses to contrasting environments. We found similar geographic variation in the level of genetic diversity in the sister species Oxyrrhis maritima. Because the capacity for wide dispersal is not always realized, historic genetic footprints of range expansion and contraction persist in contemporary populations of marine microbes, as they do in larger species. Indeed, the well-described genetic effects of climatic variation on macroorganisms provide clear, testable hypotheses about the processes that drive genetic divergence in marine microbes and thus about the response to future environmental change.
自由生活的海洋微生物表现出多样的空间遗传结构的机制仍然存在争议，大多数研究强调了高迁移能力，这应该重新分配遗传多样性，而与大多数大型生物相反，其种群通常保留了对历史气候波动的种群响应的遗传特征。我们量化了海洋鞭毛虫 Oxyrrhis marina 的欧洲系统地理学结构，发现西北大西洋和地中海之间的空间遗传结构、种群动态和遗传多样性存在显著差异，这反映了这些地区的持续分离以及对不同环境的种群响应的背景依赖性。我们发现姐妹种 Oxyrrhis maritima 的遗传多样性水平也存在类似的地理变异。因为广泛迁移的能力并不总是能够实现，所以海洋微生物的当代种群中仍然存在着范围扩张和收缩的历史遗传痕迹，就像在更大的物种中一样。事实上，气候变化对大型生物的遗传影响很好地描述了驱动海洋微生物遗传分化的过程，从而为未来环境变化的响应提供了明确、可检验的假设。
