Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37, 08003, Barcelona, Spain.
Indurot, Universidad de Oviedo, Campus de Mieres, 33600, Mieres, Asturias, Spain.
Sci Rep. 2019 Nov 22;9(1):17375. doi: 10.1038/s41598-019-53891-y.
When a population shows a marked morphological change, it is important to know whether that population is genetically distinct; if it is not, the novel trait could correspond to an adaptation that might be of great ecological interest. Here, we studied a subspecies of water shrew, Neomys fodiens niethammeri, which is found in a narrow strip of the northern Iberian Peninsula. This subspecies presents an abrupt increase in skull size when compared to the rest of the Eurasian population, which has led to the suggestion that it is actually a different species. Skulls obtained from owl pellets collected over the last 50 years allowed us to perform a morphometric analysis in addition to an extensive multilocus analysis based on short intron fragments successfully amplified from these degraded samples. Interestingly, no genetic divergence was detected using either mitochondrial or nuclear data. Additionally, an allele frequency analysis revealed no significant genetic differentiation. The absence of genetic divergence and differentiation revealed here indicate that the large form of N. fodiens does not correspond to a different species and instead represents an extreme case of size increase, of possible adaptive value, which deserves further investigation.
当一个种群表现出明显的形态变化时，了解该种群是否在遗传上具有独特性非常重要；如果不是，那么新的特征可能对应于一种具有重要生态意义的适应性特征。在这里，我们研究了一种生活在伊比利亚半岛北部狭长地带的水鼩亚种，即沼泽田鼠指名亚种。与欧亚大陆其他地区的种群相比，该亚种的头骨大小突然增大，这导致有人提出它实际上是一个不同的物种。我们从过去 50 年中从猫头鹰粪便中获得的头骨进行了形态测量分析，此外还对从这些降解样本中成功扩增的短内含子片段进行了广泛的多基因座分析。有趣的是，线粒体或核数据都没有检测到遗传分化。此外，等位基因频率分析显示没有明显的遗传分化。这里揭示的遗传分化和差异的缺失表明，N. fodiens 的大型形态并不代表一个不同的物种，而是代表了一种可能具有适应价值的体型增大的极端情况，值得进一步研究。
