Complete sequence and characterization of the channel catfish mitochondrial genome.

In order to support analysis of channel catfish populations and genetic improvement programs, the channel catfish, Ictalurus punctatus, mitochondrial genome was completely sequenced and revealed gene structure and gene order common to vertebrates. Nucleotide sequence comparisons of cytochrome b (Cytb) and cytochrome c oxidase subunit 1 (COI) demonstrated genetic separation of the genera Ictalurus, Pylodictis and Ameiurus consistent with the taxonomic classification within Ictaluridae. The ictalurid Cytb nucleotide sequences were significantly different from a putative channel catfish Cytb sequence in GenBank. Genetic relationships based on mitochondrial DNA sequences indicated the value of channel catfish in genomic comparisons between teleosts. Pairwise alignment of DNA sequences revealed conservation of regulatory sequences in the D-loop region with other vertebrates. Analysis of D-loop sequences in commercial populations and a research strain revealed 28 polymorphic sites and 33 D-loop haplotypes. Sequence analysis revealed clustering of haplotypes within commercial farms and the USDA103 research line, but D-loop haplotypes were not sufficient to discriminate the USDA103 fish from commercial catfish.