DNA barcoding for squids of the family Gonatidae (Cephalopoda: Teuthida) from the boreal North Pacific.

A fragment of cytochrome c oxidase I was used to assess whether species of the squid family Gonatidae from the North Pacific could be identified using DNA barcoding approach. Pairwise intra- and interspecific p-distances were assessed, and systematic relationships among species were estimated by NJ analysis. Examined species formed well-differentiated species-specific clades on the neighbor-joining and Bayesian trees.

Cytochrome oxidase 1 gene sequence analysis in six flatfish species (Teleostei, Pleuronectidae) of Far East Russia with inferences in phylogeny and taxonomy.

Mitochondrial DNA at the cytochrome oxidase 1 (Co-1) gene region was sequenced for six flatfish species (in total, 11 sequences of at least 539 base pairs) from the Far East of Russia and compared with other sequences of Pleuronectiformes, comprising altogether 26 flatfish sequences and two outgroup sequences (Perciformes). An analysis of the protein-coding Co-1 gene revealed a statistically substantiated bias in (T + C):(A + G) content, supporting earlier findings. Average scores of the p-distances for different scales of the evolutionary history at the Co-1 gene revealed a clear pattern of increased nucleotide diversity at four different levels: (1) intraspecies, (2) intragenus, (3) intrafamily, and (4) intra-order.