Jiménez Ares, Weigelt Barbara, Santos-Guerra Arnoldo, Caujapé-Castells Juli, Fernández-Palacios José María, Conti Elena
Department of Systematic and Evolutionary Botany and Botanical Garden, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland.
Instituto Canario de Investigaciones Agrarias, Calle Guaidil 16, 38280, Tegueste, Tenerife, Spain.
Genetica. 2017 Feb;145(1):91-104. doi: 10.1007/s10709-017-9948-z. Epub 2017 Jan 20.
Oceanic archipelagos are typically rich in endemic taxa, because they offer ideal conditions for diversification and speciation in isolation. One of the most remarkable evolutionary radiations on the Canary Islands comprises the 16 species included in Limonium subsection Nobiles, all of which are subject to diverse threats, and legally protected. Since many of them are single-island endemics limited to one or a few populations, there exists a risk that a loss of genetic variation might limit their long-term survival. In this study, we used eight newly developed microsatellite markers to characterize the levels of genetic variation and inbreeding in L. macrophyllum, a species endemic to the North-east of Tenerife that belongs to Limonium subsection Nobiles. We detected generally low levels of genetic variation over all populations (H = 0.363), and substantial differentiation among populations (F = 0.188; R = 0.186) coupled with a negligible degree of inbreeding (F = 0.042). Obligate outcrossing may have maintained L. macrophyllum relatively unaffected by inbreeding despite the species' limited dispersal ability and the genetic bottlenecks likely caused by a prolonged history of grazing. Although several factors still constitute a risk for the conservation of L. macrophyllum, the lack of inbreeding and the recent positive demographic trends observed in the populations of this species are factors that favour its future persistence.
海洋群岛通常拥有丰富的特有分类群，因为它们为隔离状态下的多样化和物种形成提供了理想条件。加那利群岛最显著的进化辐射之一包括补血草属高贵组中的16个物种，所有这些物种都面临着各种威胁，并受到法律保护。由于它们中的许多是单岛特有种，仅限于一个或几个种群，因此存在遗传变异丧失可能限制其长期生存的风险。在本研究中，我们使用了八个新开发的微卫星标记来表征大叶补血草的遗传变异水平和近亲繁殖情况，大叶补血草是特内里费岛东北部的特有物种，属于补血草属高贵组。我们检测到所有种群的遗传变异水平普遍较低（H = 0.363），种群间存在显著分化（F = 0.188；R = 0.186），同时近亲繁殖程度可忽略不计（F = 0.042）。尽管该物种的扩散能力有限且长期放牧可能导致遗传瓶颈，但专性异交可能使大叶补血草相对不受近亲繁殖的影响。尽管有几个因素仍然对大叶补血草的保护构成风险，但该物种种群中缺乏近亲繁殖以及近期观察到的积极种群动态趋势是有利于其未来存续的因素。
