Distance, flow and PCR inhibition: eDNA dynamics in two headwater streams
Distance, flow and PCR inhibition: eDNA dynamics in two headwater streams
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DOI：
10.1111/1755-0998.12285
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发表时间：
2015-01-01
影响因子：
7.7
通讯作者：
Whiteley, Andrew R.
中科院分区：
文献类型：
--
作者：
Jane, Stephen F.;Wilcox, Taylor M.;Whiteley, Andrew R.
环境DNA（eDNA）检测已成为监测水生生物的有力工具，但关于在一系列环境条件下水生eDNA的动态仍有许多未知之处。溪流和河流中的DNA浓度不仅取决于进入水中的DNA和通过降解离开系统的DNA之间的平衡，而且还取决于下游运输。为了提高了解的动态eDNA浓度在lotic系统中，我们引入了两个无鱼的源头流，并采取eDNA样本均匀分布的下游间隔的笼鳟鱼。从仲夏到秋天，在大约1- 96 L/s的流量范围内重复了18次。我们使用定量PCR将DNA拷贝数与距离源的距离相关联。我们发现，无论流量如何，在239.5米处都有可检测到的DNA水平。流动对eDNA计数的主要影响是在两个流中的相反方向。在最低的流量，eDNA计数最高接近源，并迅速落后的距离。在最高流量，DNA计数相对较低，无论是附近和远离源。生物量呈正相关eDNA拷贝数在这两个流。细胞沉降、湍流和稀释效应的组合可能是我们观察到的原因。此外，在高叶沉积期间，抑制剂的存在导致在不存在抑制释放策略的情况下高拷贝数样品没有扩增，这表明在eDNA分析中仔细考虑抑制的必要性。
Environmental DNA (eDNA) detection has emerged as a powerful tool for monitoring aquatic organisms, but much remains unknown about the dynamics of aquatic eDNA over a range of environmental conditions. DNA concentrations in streams and rivers will depend not only on the equilibrium between DNA entering the water and DNA leaving the system through degradation, but also on downstream transport. To improve understanding of the dynamics of eDNA concentration in lotic systems, we introduced caged trout into two fishless headwater streams and took eDNA samples at evenly spaced downstream intervals. This was repeated 18 times from mid-summer through autumn, over flows ranging from approximately 1-96L/s. We used quantitative PCR to relate DNA copy number to distance from source. We found that regardless of flow, there were detectable levels of DNA at 239.5m. The main effect of flow on eDNA counts was in opposite directions in the two streams. At the lowest flows, eDNA counts were highest close to the source and quickly trailed off over distance. At the highest flows, DNA counts were relatively low both near and far from the source. Biomass was positively related to eDNA copy number in both streams. A combination of cell settling, turbulence and dilution effects is probably responsible for our observations. Additionally, during high leaf deposition periods, the presence of inhibitors resulted in no amplification for high copy number samples in the absence of an inhibition-releasing strategy, demonstrating the necessity to carefully consider inhibition in eDNA analysis.