title: Transcriptomic comparison of invasive bigheaded carps (Hypophthalmichthys nobilisandHypophthalmichthys molitrix) and their hybrids.
abstract: Bighead carp(Hypophthalmichthys nobilis) and silver carp (Hypophthalmichthys molitrix), 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, F1hybrid, 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 F1hybrids 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.
authors.affiliation: 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.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Biological Sciences Western Illinois University Macomb IL 61455 USA.
authors.forename: James T
authors.initials: JT
authors.lastname: Lamer
authors.affiliation: Department of Biology University of Nebraska at Omaha Omaha NE 68182 USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Gaughan
authors.affiliation: Department of Biology University of Nebraska at Omaha Omaha NE 68182 USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Wachholtz
authors.affiliation: Key Laboratory of Freshwater Fisheries Germplasm Resources Ministry of Agriculture Shanghai Ocean University Shanghai 201306 China.
authors.forename: Chenghui
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Biology University of Nebraska at Omaha Omaha NE 68182 USA; School of Interdisciplinary Informatics University of Nebraska at Omaha Omaha NE 68182 USA.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Lu
keywords: bigheaded carps; hybridization; invasion; transcriptomes