Comparing spatial patterns of population density, biomass, and genetic diversity patterns of the habitat generalist mayfly Isonychia japonica Ulmer (Ephemeroptera:Isonychiidae) in the Chikuma–Shinano River basin
Comparing spatial patterns of population density, biomass, and genetic diversity patterns of the habitat generalist mayfly Isonychia japonica Ulmer (Ephemeroptera:Isonychiidae) in the Chikuma–Shinano River basin
复制标题
筑马-信浓川流域栖息地通才蜉蝣Isonychia japonica Ulmer（蜉蝣目：Isonychiidae）种群密度、生物量和遗传多样性空间格局的比较
作者：
Rie Saito;K. Tojo
评估河流景观中河流内部和河流之间的种群相对连通性对于更好地了解河流生态至关重要。分子标记为评估种群的连通性和评估种群的固有属性，如遗传多样性提供了一种合理的方法。许多以前在区域一级对物种内遗传分化的研究都集中在栖息地专家身上，但栖息地通才并不是研究的重点，因为他们在各种不同的栖息地连续而广泛地分布。我们在日本群岛最大的水系--千间新野河流域的42个研究地点对一种典型的栖息地通用型蚂蚁--日本等脚甲进行了研究，评估了它的种群密度、生物量和遗传结构。我们对线粒体DNA细胞色素氧化酶C亚基I(COI)区(610个碱基对)进行了遗传分析。我们证实，日本血吸虫在整个流域内从上下游栖息地到∼有300公里的大范围栖息。对330个样本的遗传分析表明，无论种群密度或生物量如何，每个研究地点的遗传多样性都非常高。在许多情况下，即使在遥远的研究地点之间，样本也共享相同的单倍型。在江河流域广泛观察到一种优势单倍型。估计的基因流动的方向和强度支持这样的假设，即所有方向都发生了高基因流动。基因流动的模式似乎不受不合适的栖息地或低人口密度或低生物量区域的影响。我们认为，日本血吸虫具有集合种群遗传结构，其中低密度的种群由不断涌入的移民维持。
Evaluating the relative connectivity of populations within and among streams in a riverine landscape is crucial to developing a better understanding of stream ecology. Molecular markers provide a reasonable approach to assess the connectivity of populations and to evaluate inherent properties of populations, such as genetic diversity. Many previous investigators of genetic differentiation within species at the regional level have focused on habitat specialists, but habitat generalists, with their continuous and broad distribution across a wide variety of habitats, have not been a focus of research. We examined a typical habitat generalist mayfly, Isonychia japonica Ulmer (Ephemeroptera:Isonychiidae) by evaluating its population density, biomass, and genetic structure at 42 study sites in the largest river system in the Japanese Archipelago, the Chikuma–Shinano-gawa River basin. We conducted genetic analysis of the mitochondrial DNA cytochrome oxidase c subunit I (COI) region (610 base pairs). We confirmed that I. japonica inhabits an extensive range of ∼300 km from its up- to downstream habitats throughout the watershed. Genetic analysis of 330 specimens showed that genetic diversity at each study site was extremely high, regardless of the respective population density or biomass. In many cases, specimens shared the same haplotypes even between distant study sites. One dominant haplotype was widely observed in the river basin. The direction and strength of the estimated gene flow supported the hypothesis that high gene flow has occurred in all directions. The pattern of gene flow does not appear to be affected by unsuitable habitat areas or areas of low population density or low biomass. We argue that I. japonica has a metapopulation genetic structure, where low-density demes are sustained by a continual influx of immigrants.
影响因子：
3.3
作者：
Yunxin Fu
通讯作者：
Yunxin Fu