Mitochondrial DNA (mtDNA) regions have been widely used as molecular markers in evolutionary studies and species identification. However, the presence of heteroplasmy and NUMTs may represent obstacles. Heteroplasmy is a state where an organism has different mitochondrial haplotypes. NUMTs are nuclear pseudogenes originating from mtDNA sequences transferred to nuclear DNA. Evidences of heteroplasmy were already verified in the bumblebee Bombus morio in an earlier study. The present work investigated in more detail the presence of intra-individual haplotypes variation in this species. Heteroplasmy was detected in individuals from all the ten sampled locations, with an average of six heteroplasmic haplotypes per individual. In addition, some of these heteroplasmic haplotypes were shared among individuals from different locations, suggesting the existence of stable heteroplasmy in B. morio. These results demonstrated that heteroplasmy is likely to affect inferences based on mtDNA analysis, especially in phylogenetic, phylogeographic and population genetics studies. In addition, NUMTs were also detected. These sequences showed divergence of 2% to 12% in relation to the mitochondrial haplotypes. These levels of divergence could mislead conclusions in evolutionary studies and affect species identification through DNA barcoding.

中文翻译：

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大黄蜂物种的线粒体 DNA 个体内变异：进化研究和分子鉴定的挑战

线粒体 DNA (mtDNA) 区域已被广泛用作进化研究和物种鉴定中的分子标记。然而，异质性和 NUMT 的存在可能代表障碍。异质性是一种生物体具有不同线粒体单倍型的状态。NUMT 是源自转移到核 DNA 的 mtDNA 序列的核假基因。在早期的一项研究中，已经在大黄蜂 Bombus morio 中证实了异质性的证据。目前的工作更详细地研究了该物种中个体内单倍型变异的存在。在来自所有十个采样位置的个体中检测到异质性，每个个体平均有六个异质性单倍型。此外，其中一些异质单倍型在来自不同地点的个体之间共享，表明 B. morio 中存在稳定的异质性。这些结果表明，异质性可能会影响基于 mtDNA 分析的推论，尤其是在系统发育、系统地理学和群体遗传学研究中。此外，还检测到 NUMT。这些序列显示出与线粒体单倍型相关的 2% 至 12% 的差异。这些差异程度可能会误导进化研究的结论，并通过 DNA 条形码影响物种识别。