Molecular patterns of adaptive variation in spruces

北方云杉是自然分布最广的生物之一。它们一般具有遗传多样性高、种群规模大的特点。这些物种直到最近才在冰川消退后重新整合了它们的活动范围。相比之下，亚热带云杉的分布范围要小得多，它们的出现仅限于高海拔地区。它们的遗传多样性普遍减少，并且随着全新世的变暖，它们的活动范围一直在缩小。然而，目前尚不清楚这种差异是否会反映在适应性遗传变异的水平上，因为类似的适应可能已经进化到在南方或北纬的高海拔地区的寒冷气候中生存下来。我们研究项目的目标是在分子水平上破译长寿命的未驯化生物（如针叶树）的适应结构。其中一个主要目的是识别具有适应性遗传变异的基因，并评估适应性变异的模式如何在云杉之间相互关联。未驯化植物种群遗传学研究的一个主要障碍是普遍缺乏与适应或其他重要数量性状相关的分子遗传标记。最近，我们已经证明，利用涉及数百个基因的基因组的离群值识别扫描，有可能识别出潜在参与适应性遗传变异的基因多态性（SNPs）。基于这些结果，适应性异常snp的大范围变异模式将被研究。选择签名将进一步筛选云杉基因家族与最近的重复。一组同源基因跨越基因组将在不同的云杉物种测序，以确定他们的分子适应系数。这项研究计划将产生新的遗传标记，以便监测云杉遗传景观中的适应性基因变异。这些标记将有助于估计不同物种间适应性基因含量的重叠，更好地了解基因水平上的适应性动态。它们将允许更好地监测适应性遗传资源，这正成为一项紧迫的任务，特别是对濒临灭绝的亚热带物种。

Boreal spruces are among living organisms with the largest natural distributions. They are generally characterized by high genetic diversity and large population size. These species have only recently re-integrated their ranges following the retreat of glaciers. In contrast, subtropical spruces have much smaller distribution ranges and their occurrence is limited to areas of high altitude. They generally harbor reduced genetic diversity and have suffered an on-going range contraction with the Holocene warming. However, it is not clear if such differences would be reflected at the level of adaptive genetic variation, given that similar adaptations might have evolved to survive colder climates at higher elevations in the south or at northern latitudes. The goal of our research program is to decipher the architecture of adaptation at the molecular level in long-lived undomesticated organisms such as conifers. One major aim is to identify genes harboring adaptive genetic variation and evaluate how patterns of adaptive variation are correlated among spruces. A main obstacle in population genetics of undomesticated plant species is the general lack of molecular genetic markers related to adaptation or other important quantitative traits. Recently, we have shown that it was possible to identify gene polymorphisms (SNPs) potentially involved in adaptive genetic variation, using outlier identification scans of the genome implicating hundreds of genes. Based on these results, range-wide patterns of variation for adaptive outlier SNPs will be investigated. Selection signatures will further be screened in spruce gene families with recent duplicates. A homeologous set of genes spanning the genome will be sequenced in different spruce species to determine their coefficient of molecular adaptation. This research program should result in new genetic markers allowing to monitor adaptive gene variation across spruce genetic landscapes. These markers will allow to estimate the overlap in adaptive gene content among different species and better understand the dynamics of adaptation at the gene level. They will allow to better monitor adaptive genetic resources, which is becoming an urgent task, particularly for endangered subtropical species.