Adaptation to environmental warming? Microevolution in the protists Paramecium and Coleps

全球变暖将如何影响生态群落的物种多样性已经在各种研究中得到了证明。然而，只有少数研究测试了环境变暖如何影响种群的遗传变异，以及这可能如何反过来改变生态群落中的相互作用。尽管选择实验是解决这些问题的唯一合适的工具，但几乎没有人对水生生物进行过选择实验。本文拟以尾草履虫为实验对象，研究全球变暖对种群遗传结构的影响。由于生成时间快，它非常适合这些实验，特别是对于冬季平均温度的增加。一个物种内的种群或世系对当地普遍温度和温度变化的适应程度可能对种群在可能迅速变化的热环境下的生存和遗传组成具有重要影响。因此，我们收集了克隆谱系的实验种群，它们起源于整个欧洲的池塘和溪流种群。使用分子方法，我们能够在选择实验中检测单个谱系。我们将测试a)夏季和冬季平均温度的升高是否会减少实验种群的遗传变异，b)极端温度的增加是否会减少实验种群的遗传变异，以及这种影响对河流种群是否比池塘种群更强，池塘种群在自然栖息地经历的温度变化比河流种群更强。最后，我们想测试是否由于种群的遗传变化，细菌（大肠杆菌）和尾尾假单胞菌之间的捕食者-猎物关系会出现不匹配。

How global warming will affect the species diversity of ecological communities has been shown in a variety of studies. However, only a few studies have tested how environmental warming may affect the genetic variation of populations and how this might change in turn the interactions in ecological communities. Although selection experiments are an uniquely suited tool to address these questions, almost none have been performed for aquatic organisms. Here we propose to use Paramecium caudatum as an ideal organism to perform experiments, which test the influence of global warming on the genetic structure of populations. Due to fast generation time, it is well suited for these experiments, this is specifically the case for the increase in average winter temperatures. The extent to which populations or lineages within a species are locally adapted to the prevailing temperatures and temperature changes may have strong implications for the population survival and genetic composition under a potentially rapidly changing thermal regime. Consequently, we assemble experimental populations of clonal lineages, which originate from pond and stream populations throughout Europe. Using molecular methods, we are able to detect individual lineages within a selection experiment. We will test a) if elevated average summer and winter temperatures and b) an increase in temperature extremes will reduce the genetic variation of this experimental population and if this effect is stronger for the stream populations than for the pond populations, which experience in their natural habitat stronger temperature changes than the stream populations. Eventually, we would like to test if due to the genetic change of the populations it would come to a mismatch in the predator-prey relationship between bacteria (Escherichia coli) and P. caudatum.