Wang Jun, Lamer James T, Gaughan Sarah, Wachholtz Michael, Wang Chenghui, Lu Guoqing
Department of Biology University of Nebraska at Omaha Omaha NE 68182 USA; Key Laboratory of Freshwater Fisheries Germplasm Resources Ministry of Agriculture Shanghai Ocean University Shanghai 201306 China.
Department of Biological Sciences Western Illinois University Macomb IL 61455 USA.
Ecol Evol. 2016 Oct 27;6(23):8452-8459. doi: 10.1002/ece3.2574. eCollection 2016 Dec.
Bighead carp ) and silver carp (), collectively called bigheaded carps, are invasive species in the Mississippi River Basin (MRB). Interspecific hybridization between bigheaded carps has been considered rare within their native rivers in China; however, it is prevalent in the MRB. We conducted de novo transcriptome analysis of pure and hybrid bigheaded carps and obtained 40,759 to 51,706 transcripts for pure, F hybrid, and backcross bigheaded carps. The search against protein databases resulted in 20,336-28,133 annotated transcripts (over 50% of the transcriptome) with over 13,000 transcripts mapped to 23 Gene Ontology biological processes and 127 KEGG metabolic pathways. More transcripts were detected in silver carp than in bighead carp; however, comparable numbers of transcripts were annotated. Transcriptomic variation detected between two F hybrids may indicate a potential loss of fitness in hybrids. The neighbor-joining distance tree constructed using over 2,500 one-to-one orthologous sequences suggests transcriptomes could be used to infer the history of introgression and hybridization. Moreover, we detected 24,792 candidate SNPs that can be used to identify different species. The transcriptomes, orthologous sequences, and candidate SNPs obtained in this study should provide further knowledge of interspecific hybridization and introgression.
鳙鱼和鲢鱼统称为“胖头鲤”，是密西西比河流域（MRB）的入侵物种。在中国本土河流中，胖头鲤之间的种间杂交被认为很少见；然而，在密西西比河流域却很普遍。我们对纯种和杂交胖头鲤进行了从头转录组分析，获得了纯种、F1杂种和回交胖头鲤的40759至51706条转录本。在蛋白质数据库中进行搜索，得到了20336至28133条注释转录本（超过转录组的50%），其中超过13000条转录本映射到23个基因本体生物学过程和127条KEGG代谢途径。在鲢鱼中检测到的转录本比鳙鱼多；然而，注释的转录本数量相当。在两个F1杂种之间检测到的转录组变异可能表明杂种存在潜在的适应性损失。使用超过2500个一对一直系同源序列构建的邻接距离树表明，转录组可用于推断渐渗和杂交的历史。此外，我们检测到24792个候选单核苷酸多态性（SNP），可用于识别不同物种。本研究中获得的转录组、直系同源序列和候选SNP应能提供有关种间杂交和渐渗的更多知识。
