Seppä Perttu, Bonelli Mariaelena, Dupont Simon, Hakala Sanja Maria, Bagnères Anne-Geneviève, Lorenzi Maria Cristina
Centre of Excellence in Biological Interactions, Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland.
Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Torino, Italy.
Insects. 2020 Sep 1;11(9):585. doi: 10.3390/insects11090585.
The co-evolutionary pathways followed by hosts and parasites strongly depend on the adaptive potential of antagonists and its underlying genetic architecture. Geographically structured populations of interacting species often experience local differences in the strength of reciprocal selection pressures, which can result in a geographic mosaic of co-evolution. One example of such a system is the boreo-montane social wasp and its social parasite , which have evolved local defense and counter-defense mechanisms to match their antagonist. In this work, we study spatial genetic structure of and populations at local and regional scales in the Alps, by using nuclear markers (DNA microsatellites, AFLP) and mitochondrial sequences. Both the host and the parasite populations harbored similar amounts of genetic variation. Host populations were not genetically structured at the local scale, but geographic regions were significantly differentiated from each other in both the host and the parasite in all markers. The net dispersal inferred from genetic differentiation was similar in the host and the parasite, which may be due to the annual migration pattern of the parasites between alpine and lowland populations. Thus, the apparent dispersal barriers (i.e., high mountains) do not restrict gene flow as expected and there are no important gene flow differences between the species, which contradict the hypothesis that restricted gene flow is required for local adaptations to evolve.
宿主和寄生虫所遵循的共同进化路径在很大程度上取决于拮抗者的适应潜力及其潜在的遗传结构。相互作用物种的地理结构化种群常常在相互选择压力的强度上经历局部差异，这可能导致共同进化的地理镶嵌体。这样一个系统的一个例子是北方山地社会黄蜂及其社会寄生虫，它们已经进化出局部防御和反防御机制来匹配它们的拮抗者。在这项工作中，我们通过使用核标记（DNA微卫星、AFLP）和线粒体序列，在阿尔卑斯山的局部和区域尺度上研究黄蜂和寄生虫种群的空间遗传结构。宿主和寄生虫种群都拥有相似数量的遗传变异。宿主种群在局部尺度上没有遗传结构，但在所有标记中，宿主和寄生虫的地理区域彼此之间都有显著差异。从遗传分化推断出的宿主和寄生虫的净扩散相似，这可能是由于寄生虫在高山和低地种群之间的年度迁移模式。因此，明显的扩散障碍（即高山）并没有像预期的那样限制基因流动，并且物种之间没有重要的基因流动差异，这与局部适应进化需要限制基因流动的假设相矛盾。
