The complete mitochondrial genome of the fine flounder Paralichthys adspersus revealed by next-generation sequencing.

The complete mitochondrial genome of the fine flounder Paralichthys adspersus, was determined for the first time through Next Generation Sequencing (NGS) approach. The mitogenome (GenBank accession no. MW288827) has 17,060 bp in length and consisted of the well-known 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and the control region. The overall nucleotide composition of the whole mitogenome was A: 27.5%, C: 29.5%, G: 17.1%, and T: 25.9%. Phylogenetic analyses based on 12 protein-coding genes clustered P. adspersus in the monophyletic Paralichthyidae clade, showing the closest phylogenetic relationship with its congeneric species P. olivaceus.

A glimpse into the genetic diversity of the Peruvian seafood sector: Unveiling species substitution, mislabeling and trade of threatened species.

Peru is one of the world's leading fishing nations and its seafood industry relies on the trade of a vast variety of aquatic resources, playing a key role in the country's socio-economic development. DNA barcoding has become of paramount importance for systematics, conservation, and seafood traceability, complementing or even surpassing conventional identification methods when target organisms show similar morphology during the early life stages, have recently diverged, or have undergone processing. Aiming to increase our knowledge of the species diversity available across the Peruvian supply chain (from fish landing sites to markets and restaurants), we applied full and mini-barcoding approaches targeting three mitochondrial genes (COI, 16S, and 12S) and the control region to identify samples purchased at retailers from six departments along the north-central Peruvian coast. DNA barcodes from 131 samples were assigned to 55 species (plus five genus-level taxa) comprising 47 families, 24 orders, and six classes including Actinopterygii (45.03%), Chondrichthyes (36.64%), Bivalvia (6.87%), Cephalopoda (6.11%), Malacostraca (3.82%), and Gastropoda (1.53%). The identified samples included commercially important pelagic (anchovy, bonito, dolphinfish) and demersal (hake, smooth-hound, Peruvian rock seabass, croaker) fish species. Our results unveiled the marketing of protected and threatened species such as whale shark, Atlantic white marlin, smooth hammerhead (some specimens collected during closed season), shortfin mako, and pelagic thresher sharks. A total of 35 samples (26.72%) were mislabeled, including tilapia labeled as wild marine fish, dolphinfish and hake labeled as grouper, and different shark species sold as "smooth-hounds". The present study highlights the necessity of implementing traceability and monitoring programs along the entire seafood supply chain using molecular tools to enhance sustainability efforts and ensure consumer choice.

Mitochondrial genome of the Peruvian scallop Argopecten purpuratus (Bivalvia: Pectinidae).

The mitochondrial genome of the Peruvian scallop Argopecten purpuratus was determined. The length of the mitochondrial coding region is 15,608 bp. A typical bivalve mitochondrial composition was detected with 12 protein-coding genes, 2 ribosomal RNA genes and 21 transfer RNA genes, with the absence of the atp8 gene. Fifty percent of the protein-coding genes use typical ATG start codon, whereas five genes utilize ATA as their start codon. Only one gene was found to utilize TTG as its start codon. The A. purpuratus mitogenome shows a significant similarity to that of A. irradians irradians, in length as well as in gene composition.

Genetic structure of the Peruvian scallop Argopecten purpuratus inferred from mitochondrial and nuclear DNA variation.

The population genetic structure of the Peruvian scallop Argopecten purpuratus from three different wild populations along the Peruvian coast was analyzed using nine microsatellite loci and a partial region (530bp) of the mitochondrial 16S rRNA gene. A total of 19 polymorphic sites in the 16S rRNA gene defined 18 unique haplotypes. High genetic diversity was presented in all populations. Statistical analysis of mitochondrial DNA revealed no significant genetic structure (ΦST=0.00511, P=0.32149) among the three localities. However, microsatellite analysis showed low (2.86%) but highly significant (P=0.0001) genetic differentiation among populations, most of the variation was found in Independencia Bay population, which is located in the Peruvian National Reserve of Paracas. Neutrality tests based on mitochondrial haplotypes were performed to assess signatures of recent historical demographic events. Overall results from Tajima's D and Fu's FS tests indicated significant deviations from neutrality. To our knowledge, this study constitutes the first investigation based on mitochondrial and microsatellite markers on the genetic structure of A. purpuratus.