ISYEB Institut, UMR 7205 CNRS-EPHE-MNHN-UPMC, Equipe Exploration, Espèces et Evolution, Muséum National d'Histoire Naturelle, case postale N° 39, 57 rue Cuvier, 75231, Cedex 05 Paris, France; CNRS, UMR 7144 Adaptation et Diversité en Milieu Marin, Equipe BEDIM, Station Biologique de Roscoff, CS 90074, 29688, Roscoff, France; Sorbonne Universités, UPMC Univ Paris 06, UMR 7144 Adaptation et Diversité en Milieu Marin, Equipe BEDIM, Station Biologique de Roscoff, CS 90074, 29688, Roscoff, France.
Mol Ecol. 2014 Jun;23(11):2669-85. doi: 10.1111/mec.12774.
We investigated patterns of genetic structure in two sister kelp species to explore how distribution width along the shore, zonation, latitudinal distribution and historical factors contribute to contrasting patterns of genetic diversity. We implemented a hierarchical sampling scheme to compare patterns of genetic diversity and structure in these two kelp species co-distributed along the coasts of Brittany (France) using a total of 12 microsatellites, nine for Laminaria hyperborea and 11 for Laminaria digitata, of which eight amplified in both species. The genetic diversity and connectivity of L. hyperborea populations were greater than those of L. digitata populations in accordance with the larger cross-shore distribution width along the coast and the greater depth occupied by L. hyperborea populations in contrast to L. digitata populations. In addition, marginal populations showed reduced genetic diversity and connectivity, which erased isolation-by-distance patterns in both species. As L. digitata encounters its southern range limit in southern Brittany (SBr) while L. hyperborea extends down to mid-Portugal, it was possible to distinguish the effect of habitat continuity from range edge effects. We found that L. digitata did not harbour high regional diversity at its southern edge, as expected in a typical rear edge, suggesting that refuges from the last glacial maximum for L. digitata were probably not located in SBr, but most likely further north. For both species, the highest levels of genetic diversity were found in the Iroise Sea and Morlaix Bay, the two regions in which they are being currently harvested. Preserving genetic diversity of these two foundation species in these areas should, thus, be a priority for the management of this resource in Brittany.
我们研究了两种姐妹裙带菜物种的遗传结构模式，以探讨分布宽度沿海岸、分带、纬度分布以及历史因素如何影响遗传多样性的对比模式。我们实施了分层抽样方案，使用总共 12 个微卫星，其中 9 个用于巨藻，11 个用于掌状海带，这 8 个在两个物种中都有扩增，来比较这两个在布列塔尼（法国）沿海共同分布的裙带菜物种的遗传多样性和结构模式。根据巨藻种群沿海岸的更大的横向分布宽度和巨藻种群的更大的深度，与掌状海带种群相比，巨藻种群的遗传多样性和连通性较大。此外，边缘种群显示出遗传多样性和连通性降低，这消除了两个物种的隔离距离模式。由于掌状海带在布列塔尼南部（SBr）遇到其南部的范围限制，而巨藻延伸到葡萄牙中部，因此可以区分栖息地连续性的影响与范围边缘效应。我们发现，掌状海带在其南部边缘没有高的区域多样性，这在典型的后缘是预期的，这表明掌状海带的最后一个冰河时代的避难所可能不在 SBr，而更可能在北部。对于这两个物种，遗传多样性水平最高的是伊罗瓦兹海和莫尔莱湾，这两个地区是目前它们被收获的地方。在这些地区保护这两个基础物种的遗传多样性应该是布列塔尼该资源管理的优先事项。
