Center for Advanced Studies of Blanes (CEAB, CSIC), Accès a la Cala Sant Francesc 14, Blanes, Girona, Spain.
Department of Biology, Geology, Physics and Inorganic Chemistry, Rey Juan Carlos University, C/ Tulipán s/n, 28932, Móstoles, Spain.
Heredity (Edinb). 2019 Feb;122(2):244-259. doi: 10.1038/s41437-018-0098-6. Epub 2018 Jun 14.
The genetic structure of 13 populations of the amphiatlantic sea urchin Arbacia lixula, as well as temporal genetic changes in three of these localities, were assessed using ten hypervariable microsatellite loci. This thermophilous sea urchin is an important engineer species triggering the formation of barren grounds through its grazing activity. Its abundance seems to be increasing in most parts of the Mediterranean, probably favoured by warming conditions. Significant genetic differentiation was found both spatially and temporally. The main break corresponded to the separation of western Atlantic populations from those in eastern Atlantic and the Mediterranean Sea. A less marked, but significant differentiation was also found between Macaronesia (eastern Atlantic) and the Mediterranean. In the latter area, a signal of differentiation between the transitional area (Alboran Sea) and the rest of the Mediterranean was detected. However, no genetic structure is found within the Mediterranean (excluding Alboran) across the Siculo-Tunisian Strait, resulting from either enough gene flow to homogenize distance areas or/and a recent evolutionary history marked by demographic expansion in this basin. Genetic temporal variation at the Alboran Sea is as important as spatial variation, suggesting that temporal changes in hydrological features can affect the genetic composition of the populations. A picture of genetic homogeneity in the Mediterranean emerges, implying that the potential expansion of this keystone species will not be limited by intraspecific genetic features and/or potential impact of postulated barriers to gene flow in the region.
采用 10 个高变微卫星位点，评估了分布于大西洋两岸的 13 个砂海胆（Arbacia lixula）种群的遗传结构，以及其中 3 个地点的遗传时变。这种嗜热的海胆是一种重要的工程物种，通过摄食活动引发贫瘠地的形成。其丰度在大多数地中海地区似乎都在增加，可能得益于变暖的条件。无论是空间上还是时间上都发现了显著的遗传分化。主要的分化对应于大西洋西部种群与大西洋东部和地中海种群的分离。在马卡龙西亚（大西洋东部）和地中海之间也发现了一个不太明显但有显著分化的区域。在地中海地区（不包括阿尔沃兰海），在过渡区（阿尔沃兰海）和地中海其余地区之间检测到了分化的信号。然而，在西西里-突尼斯海峡处，没有发现地中海（不包括阿尔沃兰海）内部的遗传结构，这可能是由于足够的基因流使距离区域同质化，或者/和该盆地最近的进化历史以人口扩张为特征。阿尔沃兰海的遗传时变与空间变分一样重要，这表明水文学特征的时间变化可能会影响种群的遗传组成。地中海呈现出遗传同质性的图景，这意味着这种关键物种的潜在扩张不会受到种内遗传特征和/或该地区假定的基因流障碍的潜在影响的限制。
