Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
Institute of Biochemistry, Universitätsmedizin Berlin Charité, Berlin, Germany.
PLoS One. 2019 Aug 29;14(8):e0221706. doi: 10.1371/journal.pone.0221706. eCollection 2019.
In response to strong selection, new mutations can arise quickly and sweep through populations, particularly, if survival and reproduction depend on certain allele copies for adaptation to rapidly changing environments, like resistance against deadly diseases or strong toxins. Since the 1950s, resistance to anticoagulant rodenticides in several rodents has emerged through single nucleotide mutations in the vitamin-K-epoxid-reductase-complex-subunit-1 (VKORC1) gene, often located in its exon 3. Detection of high prevalence and concentrations of anticoagulant rodenticides in non-target vertebrates, including carnivorous Mustelidae, let us assume that secondary exposure by feeding on poisoned prey may also cause selection along the food chain and we hypothesized that VKORC1-based resistance might also have evolved in rodents' predators. Using newly-developed mustelid-specific primers for direct sequencing of genomic DNA, we studied VKORC1-DNA-polymorphisms in 115 mustelids of five species (Martes martes, M. foina, Mustela nivalis, M. erminea, M. putorius), obtained from northern Denmark, yielding six sites with nonsynonymous and several synonymous amino acid polymorphisms in exon 3. Comparison of these VKORC1-genotypes with hepatic rodenticide residues (obtained by HPLC combined with fluorescence or mass spectrometry) in 83 individuals (except M. martes), using generalized linear models, suggested that anticoagulant levels depended on species and specific polymorphisms. Although most VKORC-1 polymorphisms may present standing genetic variation, some are situated in resistance-mediating membrane parts of the VKORC1-encoded protein, and might be a result of selection due to exposure to anticoagulant poisons. Our new molecular markers might allow detecting indirect effects of anticoagulant rodenticides on rodent predator populations in the future.
为了应对强烈的选择压力，新的突变可以迅速出现并在种群中迅速传播，特别是如果生存和繁殖取决于某些等位基因副本来适应快速变化的环境，例如对致命疾病或强烈毒素的抵抗力。自 20 世纪 50 年代以来，几种啮齿动物对抗凝杀鼠剂的抗性是通过维生素 K 环氧化物还原酶复合物亚单位 1（VKORC1）基因中的单核苷酸突变产生的，该基因通常位于其外显子 3 中。非目标脊椎动物（包括肉食性鼬科动物）中抗凝杀鼠剂的高流行率和浓度的检测结果表明，通过摄食中毒的猎物进行二次暴露也可能导致食物链中的选择，我们假设 VKORC1 基因为基础的抗性也可能在啮齿动物的捕食者中进化。我们使用新开发的鼬科动物特异性引物对来自丹麦北部的 5 种（Martes martes、M. foina、Mustela nivalis、M. erminea、M. putorius）的 115 只鼬科动物的基因组 DNA 进行直接测序，研究了 VKORC1-DNA 多态性，在外显子 3 中发现了 6 个非同义氨基酸和几个同义氨基酸多态性位点。在 83 只个体（除了 M. martes 外）中，将这些 VKORC1 基因型与肝杀鼠剂残留（通过 HPLC 结合荧光或质谱法获得）进行比较，使用广义线性模型表明，抗凝剂水平取决于物种和特定的多态性。虽然大多数 VKORC-1 多态性可能代表着遗传变异，但有些位于 VKORC1 编码蛋白的抗性介导膜部分，可能是由于暴露于抗凝毒物而产生的选择结果。我们的新分子标记物可能允许在未来检测抗凝杀鼠剂对啮齿动物捕食者种群的间接影响。
