title: Mitochondrial Genome Variation after Hybridization and Differences in the First and Second Generation Hybrids of Bream Fishes.
abstract: Hybridization plays an important role in fish breeding. Bream fishes contribute a lot to aquaculture in China due to their economically valuable characteristics and the present study included five bream species, Megalobrama amblycephala, Megalobrama skolkovii, Megalobrama pellegrini, Megalobrama terminalis and Parabramis pekinensis. As maternal inheritance of mitochondrial genome (mitogenome) involves species specific regulation, we aimed to investigate in which way the inheritance of mitogenome is affected by hybridization in these fish species. With complete mitogenomes of 7 hybrid groups of bream species being firstly reported in the present study, a comparative analysis of 17 mitogenomes was conducted, including representatives of these 5 bream species, 6 first generation hybrids and 6 second generation hybrids. The results showed that these 17 mitogenomes shared the same gene arrangement, and had similar gene size and base composition. According to the phylogenetic analyses, all mitogenomes of the hybrids were consistent with a maternal inheritance. However, a certain number of variable sites were detected in all F1 hybrid groups compared to their female parents, especially in the group of M. terminalis (♀) × M. amblycephala (♂) (MT×MA), with a total of 86 variable sites between MT×MA and its female parent. Among the mitogenomes genes, the protein-coding gene nd5 displayed the highest variability. The number of variation sites was found to be related to phylogenetic relationship of the parents: the closer they are, the lower amount of variation sites their hybrids have. The second generation hybrids showed less mitogenome variation than that of first generation hybrids. The non-synonymous and synonymous substitution rates (dN/dS) were calculated between all the hybrids with their own female parents and the results indicated that most PCGs were under negative selection.
authors.affiliation: College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, People's Republic of China.
authors.forename: Wei-Zhuo
authors.initials: WZ
authors.lastname: Zhang
authors.affiliation: College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, People's Republic of China.
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Xiong
authors.affiliation: College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, People's Republic of China.
authors.forename: Xiu-Jie
authors.initials: XJ
authors.lastname: Zhang
authors.affiliation: College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, People's Republic of China.
authors.forename: Shi-Ming
authors.initials: SM
authors.lastname: Wan
authors.affiliation: College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, People's Republic of China.
authors.forename: Ning-Nan
authors.initials: NN
authors.lastname: Guan
authors.affiliation: College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, People's Republic of China.
authors.forename: Chun-Hong
authors.initials: CH
authors.lastname: Nie
authors.affiliation: College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, People's Republic of China.
authors.forename: Bo-Wen
authors.initials: BW
authors.lastname: Zhao
authors.affiliation: Department of Bioscience Technology, Chung Yuan Christian University, Chung-Li, Taiwan.
authors.forename: Chung-Der
authors.initials: CD
authors.lastname: Hsiao
authors.affiliation: College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China.
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Wang
authors.affiliation: College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, People's Republic of China.
authors.forename: Ze-Xia
authors.initials: ZX
authors.lastname: Gao
mesh_terms: D000818:Animals; D002678:Chimera / Q000235:genetics*; D029941:Fish Proteins / Q000235:genetics*; D005399:Fishes / Q000235:genetics*; D014644:Genetic Variation; D054629:Genome, Mitochondrial; D024101:Mitochondrial Proteins / Q000235:genetics*; D013045:Species Specificity
chemical_list: D029941:Fish Proteins; D024101:Mitochondrial Proteins