Data from: Priority effects in a planktonic bloom-forming marine diatom

Priority effects occur when a species or genotype with earlier arrival has
an advantage such that its relative abundance in the community or
population is increased compared with later-arriving species. Few studies
have dealt with this concept in the context of within-species competition.
Skeletonema marinoi is a marine diatom that shows a high degree of genetic
differentiation between populations over small geographical distances. To
test whether historical events such as priority effects may have been
important in inducing these patterns of population differentiation, we
performed microcosm experiments with successive inoculation of different
S. marinoi strains. Our results show that even in the absence of a
numerical advantage, significant priority effects were evident. We propose
that priority effects may be an important mechanism in initiating
population genetic differentiation.

优先效应（Priority effects）是指先期抵达的物种或基因型具备竞争优势，使其在群落或种群中的相对丰度高于后期抵达的物种。目前鲜有研究在种内竞争的框架下探讨这一概念。海洋骨条藻（Skeletonema marinoi）是一种海洋硅藻，其不同种群在较小地理尺度下即呈现高度显著的遗传分化。为验证优先效应等历史事件是否在驱动这类种群分化格局中发挥了关键作用，本研究通过逐步接种不同海洋骨条藻菌株的方式开展了微宇宙（microcosm）实验。研究结果显示，即便不存在初始数量优势，仍可观测到显著的优先效应。我们据此提出，优先效应可能是启动种群遗传分化的重要机制之一。