Cloning, physical mapping and genome organization of mitochondrial DNA from Cyprinus carpio oocytes

The mitochondrial genome from Cyprinus carpio oocytes is a 10.5 megadalton, circular DNA molecule. The carp mitochondrial DNA was cloned in pBR325. Three recombinant plasmids accounted for the entire genome. Mapping of this DNA using 11 different restriction endonucleases is reported here. Both the large and small rRNA genes were then localized using Southern blot analysis. The subunit I of the cytochrome oxidase, the cytochrome b, the tRNA^Glu and the URF 4 genes were localized by nucleotide sequence analysis and homology studies with human mtDNA. Our results suggest that a similar gene order has been maintained in the mitochondrial genomes of Chordata and support the hypothesis of a common ancestor for all vertebrate organelle genomes. This study constitutes the first report on the genome organization of a fish mtDNA and provides information for further investigation in connection with sequence determination, replication, and gene expression in carp mitochondria.