The zebra mussel is among the best studied freshwater molluscs in ecotoxicology, but information on the quagga mussel is lacking. Considering its potential spread, we selected a river in France in which zebra and quagga mussels coexisted, and then we used genetic markers to differentiate the two species and compared morphological parameters. cDNA sequencing assays of ten genes already used in zebra mussels were performed on quagga mussels to obtain functional specific primers. Then we analyzed the expression of genes involved in cellular metabolic activities (Cytochrome-c-oxidase – cox, and ATP synthase – atp), detoxification processes (Glutathione-S-Transferase – gst), oxidative stress (Catalase – cat), and digestive functions (Amylase – amy) on the two species. Whereas morphometric analysis underlined similarities in shape between the two species, relative gene expression profiles and metal concentrations evidenced strong differences. Quagga mussels notably presented half as high concentrations in Cd and Pb, two particularly toxic elements, as zebra mussels. These results imply that i) particular attention should be paid to properly distinguish the two species considering their similar external appearance, and ii) zebra mussels cannot be replaced by quagga mussels in ecotoxicological studies without preliminary investigations on biomarker response patterns. To our knowledge, this study is the first to have undertaken such an approach in gene expression analysis in quagga mussels, and more generally to have compared such biomarker responses of zebra and quagga mussels in the field.

斑马贻贝是生态毒理学中研究最深入的淡水软体动物之一，但缺乏有关斑马贻贝的信息。考虑到其潜在的传播，我们选择了一条法国的河流，其中斑马和斑马贻贝共存，然后我们使用遗传标记来区分这两个物种并比较了形态参数。对斑马贻贝进行了已经在斑马贻贝中使用的十个基因的cDNA测序分析，以获得功能特异性的引物。然后，我们分析了参与细胞代谢活动的基因（细胞色素c-氧化酶– cox和ATP合酶– atp），解毒过程（谷胱甘肽-S-转移酶– gst），氧化应激（Catalase – cat）的表达）和消化功能（淀粉酶–艾米）在两个物种上。形态分析强调了这两种物种在形状上的相似性，而相对基因表达谱和金属浓度却显示出很大的差异。Quagga贻贝在Cd和Pb（两种特别有毒的元素）中的高浓度是斑马贻贝的一半。这些结果表明，i）应该特别注意考虑到它们相似的外观来正确区分这两个物种，并且ii）在生态毒理学研究中，如果不对生物标志物的反应模式进行初步研究，则斑马贻贝不能被杂种贻贝替代。据我们所知，这项研究是第一个在杂种贻贝的基因表达分析中采用这种方法的研究，并且更普遍地是在该领域中比较了斑马和杂种贻贝的这种生物标志物的反应。