Genetic, morphological, and feather isotope variation of migratory willow warblers show gradual divergence in a ring
Genetic, morphological, and feather isotope variation of migratory willow warblers show gradual divergence in a ring
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DOI：
10.1111/j.1365-294x.2009.04210.x
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发表时间：
2009-07-01
影响因子：
4.9
通讯作者：
Akesson, Susanne
中科院分区：
文献类型：
--
作者：
Bensch, Staffan;Grahn, Mats;Akesson, Susanne
柳莺在波罗的海周围的圆形分布与典型的环状物种有许多共同的特征；然而，这个系统要年轻得多。先前的研究表明，次级接触带位于斯堪的纳维亚半岛中部，那里有几种形态特征的窄线，与迁徙分界线相吻合。在这里，我们分析了在波罗的海周围77个地点的繁殖地捕获的bb1700只雄性的多种特征和基因，以验证以下假设。如果斯堪的纳维亚半岛的次级接触带是末次冰期两个异域避难种群分化的结果，我们期望在圆形分布周围的其他地方找到类似的次级接触带。结果表明，在波罗的海东侧，特征线较宽且相互移位。对12个微卫星位点的分析证实，两种末端形式的基因组非常相似（F-ST = 0）。从基因组扫描中过滤掉的两个aflp衍生标记似乎是通过选择维持的。这些标记在斯堪的纳维亚半岛的次级接触带表现出陡峭的倾斜，但在表型特征方面，波罗的海以东的倾斜中心差异很大。因此，斯堪的纳维亚次接触带外沿环分布的特征线似乎是在冰川后殖民化过程中由选择或漂移的独立作用形成的。
The circular distribution of the willow warbler Phylloscopus trochilus around the Baltic Sea shares many features with the classic examples of ring species; however, the system is much younger. It has previously been shown that a secondary contact zone is located in central Scandinavia, where there are narrow clines for several morphological traits coincident with a migratory divide. Here we analyse multiple traits and genes from > 1700 males captured on breeding territories at 77 sites spread around the Baltic Sea to test the following hypothesis. If the secondary contact zone in Scandinavia is a result of divergence in two allopatric refuge populations during the last glaciation, we expect to find a similar secondary contact zone somewhere else around the circular distribution. Our results show that the trait clines were wider and displaced from each other along the eastern side of the Baltic Sea. Analyses of 12 microsatellite loci confirmed that the genome is very similar between the terminal forms (F-ST = 0). Two AFLP-derived markers filtered out from a genomic scan instead appear to be maintained by selection. These markers exhibited steep clines at the secondary contact zone in Scandinavia, but as for the phenotypic traits, had vastly different cline centres east of the Baltic Sea. The trait clines along the ring distribution outside the Scandinavian secondary contact zone thus seem to have been shaped by independent action of selection or drift during the process of postglacial colonization.