Persistent genetic signatures of colonization in Brachionus manjavacas rotifers in the Iberian Peninsula
Persistent genetic signatures of colonization in Brachionus manjavacas rotifers in the Iberian Peninsula
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DOI：
10.1111/j.1365-294x.2007.03372.x
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发表时间：
2007-08-01
影响因子：
4.9
通讯作者：
Campillo, Sergi
中科院分区：
文献类型：
--
作者：
Gomez, Africa;Montero-Pau, Javier;Campillo, Sergi
最近的系统地理学评估一致表明，尽管大陆浮游动物的滞育繁殖体具有很高的传播能力，但它们的种群细分程度很高。因此，在观察到的与远距离扩散有关的浮游动物的世界主义与区域尺度上强大的系统地理结构之间存在明显的矛盾。这种种群动态，远非迁移-漂移平衡，已经在轮虫物种复杂的臂轮虫（Brachionus plicatilis）中得到了证明，这是一群生活在世界各地盐湖和沿海泻湖的十几种物种。在这里，我们展示了这些物种之一的线粒体DNA系统地理，manjavacas Brachionus，在伊比利亚半岛，它经常与形态相似的物种B. plicatilis sensu stricto共同发生。我们从伊比利亚半岛16个湖泊和突尼斯一个湖泊的滞育卵和克隆培养物中获得233个个体的序列。发现了两个强烈支持的深层线粒体DNA分支（A和B）。系统发育和嵌套进化分析表明，进化支A具有较强的系统地理结构，与B. manjavacas进化支A和B. plicatilis s.s之间的系统地理模式具有很强的相似性，包括(i)中部和南部种群之间的异域分裂特征，以及（ii）在伊比利亚半岛的范围扩张，两者都可能发生在更新世期间。我们在瓜迪亚纳盆地发现了冰川避难所的证据。A支和B支由于活动范围扩大和次级接触而在若干湖泊中共存。B. plicatilis s.s.和B. manjavacas的共存不是最近发生的，这两个物种可能在更新世经历了类似的环境挑战。发现的遗传和地理距离的强相关性表明，历史事件可以导致这种相关性，反映了平衡种群中“距离隔离”的影响。
Recent phylogeographical assessments have consistently shown that continental zooplankton display high levels of population subdivision, despite the high dispersal capacity of their diapausing propagules. As such, there is an apparent paradox between observed cosmopolitanism in the zooplankton that is associated with long-distance dispersal, and strong phylogeographical structures at a regional scale. Such population dynamics, far from migration-drift equilibrium, have been shown in the rotifer species complex Brachionus plicatilis, a group of over a dozen species inhabiting salt lakes and coastal lagoons worldwide. Here we present the mitochondrial DNA phylogeography of one of these species, Brachionus manjavacas, in the Iberian Peninsula, where it often co-occurs with the morphologically similar species B. plicatilis sensu stricto. We obtained sequences from 233 individuals from diapausing eggs and clonal cultures from 16 lakes in the Iberian Peninsula, and a Tunisian lake. Two strongly supported deep mitochondrial DNA clades were found (A and B). Phylogenetic and nested clade analysis showed that clade A has a strong phylogeographical structure, with a strong similarity of phylogeographical patterns between B. manjavacas clade A and B. plicatilis s.s. These include (i) signatures of allopatric fragmentation between central and southern populations, and (ii) range expansions in the Iberian Peninsula, both likely to have occurred during the Pleistocene. We find evidence for a glacial refugium in the Guadiana basin. Clades A and B co-occurred in several of these lakes because of range expansion and secondary contact between both clades. The co-occurrence between B. plicatilis s.s. and B. manjavacas is not recent, and both species might have experienced similar environmental challenges during the Pleistocene. The strong correlation of genetic and geographical distance found suggests that historical events can lead to such correlation, mirroring the effects of 'isolation by distance' in equilibrium populations.