Gaetano Catanese

Evolutionary relatedness of mackerels of the genus Scomber based on complete mitochondrial genomes: Strong support to the recognition of Atlantic Scomber colias and Pacific Scomber japonicus as distinct species

Mackerels of the genus Scomber are commercially important species, but their taxonomic status is still controversial. Although previous phylogenetic data support the recognition of Atlantic Scomber colias and Pacific Scomber japonicus as separate species, it is only based on the analysis of partial mitochondrial and nuclear DNA sequences. In an attempt to shed light on this relevant issue, we have determined the complete mitochondrial DNA sequence of S. colias, S. japonicus, and Scomber australasicus. The total length of the mitogenomes was 16,568 bp for S. colias and 16,570 bp for both S. japonicus and S. australasicus. All mitogenomes had a gene content (13 protein-coding, 2 rRNAs, and 22 tRNAs) and organization similar to that observed in Scomber scombrus and most other vertebrates. The major noncoding region (control region) ranged between 865 and 866 bp in length and showed the typical conserved blocks. Phylogenetic analyses revealed a monophyletic origin of Scomber species with regard to other scombrid fish. The major finding of this study is that S. colias and S. japonicus were significantly grouped in distinct lineages within Scomber cluster, which phylogenetically constitutes evidence that they may be considered as separate species. Additionally, molecular data here presented provide a useful tool for evolutionary as well as population genetic studies.

The complete mitochondrial genome of the Senegal sole, Solea senegalensis Kaup. Comparative analysis of tandem repeats in the control region among soles

The complete nucleotide sequence of the mitochondrial genome for the Senegal sole Solea senegalensis Kaup was determined. The mitochondrial DNA was 16,659 base pairs (bp) in length. Sequence features of the 13 protein-coding genes, two ribosomal RNAs and 22 transfer RNAs are described. The non-coding control region (1017 bp) was compared with those of the closely related soles Solea solea and Solea lascaris. The typical conservative blocks were identified. A cluster of 42 and 22 tandemly arrayed repeats was detected near the 3′ end of control region in S. solea and S. lascaris, respectively. On the contrary, only two (93.8% of haplotypes) or three copies (6.2%) of an 8-bp repeated sequence motif was found in S. senegalensis. Phylogenetic analysis showed that 7 out of 9 of haplotypes bearing three copies grouped in a separate cluster. Possible mechanisms influencing the evolution of control region among soles are discussed.

Complete mitochondrial DNA sequences of the frigate tuna Auxis thazard and the bullet tuna Auxis rochei

The complete mitochondrial DNA sequence of the frigate tuna Auxis thazard and two divergent mitotypes (Mitotype I and Mitotype II) of the bullet tuna Auxis rochei have been determined. The total length of the mitogenomes was 16,506, 16,501 and 16,503 bp, respectively. All mitogenomes had a gene content (13 protein-coding, 2 rRNAs and 22 tRNAs) and organization similar to those observed in most other vertebrates. The major non-coding region (control region) ranged between 843 and 847 bp in length, and showed the typical conserved blocks. Phylogenetic analyses revealed a monophyletic origin of Auxis with respect to other tuna fish. Molecular data here presented provide a useful tool for evolutionary as well as population genetic studies.

Phylogenetic Relationships Among Ten Sole Species (Soleidae, Pleuronectiformes) from the Gulf of Cadiz (Spain) Based on Mitochondrial DNA Sequences

The entire sequence of the mitochondrial cytochrome b gene and 2 partial sequences of the ribosomal RNA12S and 16S genes have been used to study the molecular phylogeny in 10 species of soles belonging to the genera Solea, Monochirus, Microchirus, Dicologlossa, and Synaptura from the Atlantic waters of the Gulf of Cádiz (Spain). The results obtained by means of different phylogenetic analyses (maximum likelihood, maximum parsimony, and neighbor-joining) were quite similar, supporting the monophyly of the Solea species. Nevertheless, they favor the differentiation of Dicologlossa cuneata and Dicologlossa hexophthalma in 2 distinct genera, since the most closely related species to the last one is Microchirus azevia. The fact that M. azevia is also more closely linked to Monochirus hispidus than to its congeneric Microchirus boscanion argues in favor of a taxonomic reorganization of these genera.

Characterization of eight microsatellite markers in the white sea bream, Diplodus sargus (Teleostei, Sparidae)

The white sea bream, Diplodus sargus (Teleostei, Sparidae), is a species with a high commercial importance in Mediterranean aquaculture. There is currently little information available about the genetic characteristics of cultured populations. In this survey, we have developed eight polymorphic microsatellites for the white sea bream using an enriched genome library protocol. All of them were polymorphic in the 67 individuals tested, 32 of which were wild specimens, and 35 were individuals from a captive F1 broodstock. These markers can potentially be useful tools for use in population genetic studies.

Isolation and characterization of polymorphic microsatellites for the bastard sole (Microchirus azevia)

The bastard sole (Microchirus azevia) is a species of commercial interest in Spain. Nevertheless, little information is currently available about the genetic characteristics of wild populations. In this survey, we have developed eight new microsatellites using an enriched genome library protocol. Primers were screened on a total of 54 individuals from two wild populations (Mediterranean and Atlantic) from the south coast of Spain, revealing six to 18 alleles per locus with expected heterozygosities ranging from 0.51 to 0.94. These markers can potentially be useful tools for use in population genetic studies.