Evaluating mixed samples as a source of error in non‐invasive genetic studies using microsatellites
Evaluating mixed samples as a source of error in non‐invasive genetic studies using microsatellites
复制标题
评估混合样本作为使用微卫星的非侵入性遗传研究中的错误来源
作者：
David A. Roon;MIRANDA E. Thomas;K. Kendall;L. Waits
非侵入性遗传取样（NGS）在野生种群调查中的应用正在迅速增加。目前，只有有限数量的研究评估了与NGS相关的潜在偏差。本文评估了与分析来自多种动物的混合样本相关的潜在误差。大多数NGS研究假设混合样本将在基因分型过程中被识别和去除。我们通过从棕熊毛发样本中提取128个混合样本来评估这一假设。根据与其他NGS研究一致的方案，对这些混合样本进行了基因分型和6个微卫星位点的错误筛选。5个混合样本在第一次筛选后产生了可接受的基因型。然而，所有混合样品在一个或多个位点产生多个等位基因，仅作为一个源样品扩增，或者在错误检查过程的最后阶段产生不一致的电泳图。这些过程可能会潜在地减少NGS研究中观察到的个体数量，但在人口统计估计中误差应该是保守的。研究人员应该意识到混合样品的可能性，并仔细设计凝胶分析标准和错误检查方案来检测混合样品。
The use of noninvasive genetic sampling (NGS) for surveying wild populations is increasing rapidly. Currently, only a limited number of studies have evaluated potential biases associated with NGS. This paper evaluates the potential errors associated with analysing mixed samples drawn from multiple animals. Most NGS studies assume that mixed samples will be identified and removed during the genotyping process. We evaluated this assumption by creating 128 mixed samples of extracted DNA from brown bear (Ursus arctos) hair samples. These mixed samples were genotyped and screened for errors at six microsatellite loci according to protocols consistent with those used in other NGS studies. Five mixed samples produced acceptable genotypes after the first screening. However, all mixed samples produced multiple alleles at one or more loci, amplified as only one of the source samples, or yielded inconsistent electropherograms by the final stage of the error‐checking process. These processes could potentially reduce the number of individuals observed in NGS studies, but errors should be conservative within demographic estimates. Researchers should be aware of the potential for mixed samples and carefully design gel analysis criteria and error checking protocols to detect mixed samples.