title: The carp-goldfish nucleocytoplasmic hybrid has mitochondria from the carp as the nuclear donor species.
abstract: It is widely accepted that mitochondria and its DNA (mtDNA) exhibit strict maternal inheritance, with sperm contributing no or non-detectable mitochondria to the next generation. In fish, nuclear transfer (NT) through the combination of a donor nucleus and an enucleated oocyte can produce fertile nucleocytoplasmic hybrids (NCHs) even between different genera and subfamilies. One of the best studied fish NCHs is CyCa produced by transplanting the nuclei plus cytoplasm from the common carp (Cyprinus carpio var. wuyuanensis) into the oocytes of the wild goldfish (Carassius auratus), which has been propagated by self-mating for three generations. These NCH fish thus provide a unique model to study the origin of mitochondria. Here we report the complete mtDNA sequence of the CyCa hybrid and its parental species carp and goldfish as nuclear donor and cytoplasm host, respectively. Interestingly, the mtDNA of NCH fish CyCa is 99.69% identical to the nuclear donor species carp, and 89.25% identical to the oocyte host species goldfish. Furthermore, an amino acid sequence comparison of 13 mitochondrial proteins reveals that CyCa is 99.68% identical to the carp and 87.68% identical to the goldfish. On an mtDNA-based phylogenetic tree, CyCa is clustered with the carp but separated from the goldfish. A real-time PCR analysis revealed the presence of carp mtDNA but the absence of goldfish mtDNA. These results demonstrate--for the first time to our knowledge--that the mtDNA of a NCH such as CyCa fish may originate from its nuclear donor rather than its oocyte host.
authors.affiliation: Yangtze River Fisheries Research Institute, The Chinese Academy of Fisheries Sciences, Wuhan 430223, China; College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Guangfu
authors.initials: G
authors.lastname: Hu
authors.affiliation: Yangtze River Fisheries Research Institute, The Chinese Academy of Fisheries Sciences, Wuhan 430223, China. Electronic address: h1092023@hku.hk.
authors.forename: Guiwei
authors.initials: G
authors.lastname: Zou
authors.affiliation: College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Xiangjiang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Yangtze River Fisheries Research Institute, The Chinese Academy of Fisheries Sciences, Wuhan 430223, China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Liang
authors.affiliation: Yangtze River Fisheries Research Institute, The Chinese Academy of Fisheries Sciences, Wuhan 430223, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Li
authors.affiliation: Yangtze River Fisheries Research Institute, The Chinese Academy of Fisheries Sciences, Wuhan 430223, China.
authors.forename: Shaona
authors.initials: S
authors.lastname: Hu
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000235:genetics*; D000818:Animals; D002347:Carps / Q000235:genetics*; D002467:Cell Nucleus / Q000235:genetics*; D003593:Cytoplasm / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D006054:Goldfish / Q000235:genetics*; D008297:Male; D008928:Mitochondria / Q000235:genetics*; D009865:Oocytes; D010802:Phylogeny
chemical_list: D004272:DNA, Mitochondrial
keywords: ATP synthase 6 and 8; ATPase 6 and 8; COI-III; CSB; Carassius auratus; CyCa hybrid; Cyprinus carpio var. wuyuanensis; Cyt b; D-Loop; ML; NADH dehyrogenase subunits 1–6 and 4L; NCH; ND1-6 and 4L; NT; Nuclear transfer; O(L); PCR; aa; amino acid; base pair; bp; conserved sequence block; cytochrome b; cytochrome oxidase c subunits 1–3; dNTP; deoxy-ribonucleoside triphosphate; displacement loop; maximum likelihood; mitochondrial; mitochondrial DNA; mt; mtDNA; nuclear transfer; nucleocytoplasmic hybrid; origin of light-strand replication; polymerase chain reaction; rRNA; ribosomal RNA; tRNA; transfer RNA