Search

In this study, the complete mitochondrial genomes of the Mexican golden trout, Oncorhynchus chrysogaster, and Nelson's trout, O. mykiss nelsoni, were assembled and characterized. The mitogenomes were 16,655 bp and 16,661 bp long, respectively, and were composed of 13 protein-coding genes (PCGs), two ribosomal RNA genes, and 22 transfer RNA genes (all with typical 'cloverleaf' secondary structures). The length of the D-loop regions was among the longest found in Salmonids, and mitochondrial synteny in both species was identical to that reported in other Salmonids. Selective pressure analysis in the PCGs indicated that purifying selection, mainly among cox and nd genes families, likely generated the main differences between the two studied species. Nine tRNA genes showed slight differences relative to other O. mykiss subspecies, which were identical between the two study taxa. The origin of the light-strand replication has a loop that was especially large in O. mykiss nelsoni. Phylogenetic analysis indicated that O. chrysogaster and O. mykiss nelsoni are sister species, contrary to the expectation that O. chrysogaster would cluster with O. gilae. As previous studies have suggested, O. chrysogaster and O. mykiss nelsoni share common ancestry with North American trout species. [ABSTRACT FROM AUTHOR]

“Octopus” rubescens Berry, 1953 is an octopus of temperate waters of the western coast of North America. This paper presents the first record of “O.” rubescens from the tropical Mexican Pacific. Twelve octopuses were studied; 10 were collected in tide pools from five localities and two mature males were caught by fishermen in Oaxaca. We used morphometric characters and anatomical features of the digestive tract to identify the species. The five localities along the Mexican Pacific coast provide solid evidence that populations of this species have become established in tropical waters. [ABSTRACT FROM AUTHOR]

The physical location of 18S-5.8S-28S rDNA, telomeric sequences with (TTAGGG)n DNA probe and (GATA)n microsatellites were performed by fluorescence in situ hybridization in chromosomes of red abalone Haliotis rufescens. The karyotype of red abalone showed a diploid number of 36 (8M+9SM+1ST). FISH performed with rDNA probe, showed the location of major ribosomal clusters in the terminal region of the large arms of two submetacentric pairs (chromosome 4 and 5). Localization of heteromorphisms of FISH-rDNA was found between chromosome homologues and sister chromatids in all metaphases analyzed. This indicates that rDNA clusters are variable within the red abalone genome. The variability in the NOR-bearing reported using silver staining in other gastropods and our result are discussed. In addition, the presence of microsatellite (TTAGGG)n and (GATA)n was demonstrated after FISH treatment by DNA probes. The telomeric sequence occurred at the ends of all mitotic chromosomes, while the (GATA)n repetitive was found on chromosomal interstitial zones as well as at the telomeres in abalone chromosomes. [ABSTRACT FROM AUTHOR]

The California halibut, Paralichthys californicus, is a highly priced flatfish because of its size and meat quality. This work presents the complete mitochondrial genome of P. californicus. Total DNA from muscle tissue was extracted and sequenced using the Illumina platform. Reads were cleaned, trimmed, assembled de novo, and annotated. The California halibut mitogenome is 16,858 bp in length (GenBank accession number: MT859134), containing 13 protein-coding genes, 22 tRNAs, 2 rRNAs, and the control region. P. californicus mitogenome was most similar to Paralichthys olivaceus than to other flatfish mitogenomes, in agreement with their geographic distribution. This information deepens the knowledge of the California halibut, which is not only ecologically important, but also a socioeconomically relevant resource for fishery and aquaculture in California, USA, and Baja California, Mexico. [ABSTRACT FROM AUTHOR]

The red abalone Haliotis rufescens is one of the most important species for aquaculture in Baja California, México, and despite this, few gene expression studies have been done in tissues such as gill, head and gonad. For this purpose, reverse transcription and quantitative real time PCR (RT-qPCR) is a powerful tool for gene expression evaluation. For a reliable analysis, however, it is necessary to select and validate housekeeping genes that allow proper transcription quantification. Stability of nine housekeeping genes ( ACTB , BGLU , TUBB , CY , GAPDH , HPRTI , RPL5 , SDHA and UBC ) was evaluated in different tissues of red abalone (gill, head and gonad/digestive gland). Four-fold serial dilutions of cDNA (from 25 ng μL − 1 to 0.39 ng μL − 1 ) were used to prepare the standard curve, and it showed gene efficiencies between 0.95 and 0.99, with R 2 = 0.99. geNorm and NormFinder analysis showed that RPL5 and CY were the most stable genes considering all tissues, whereas in gill HPRTI and BGLU were most stable. In gonad/digestive gland, RPL5 and TUBB were the most stable genes with geNorm, while SDHA and HPRTI were the best using NormFinder. Similarly, in head the best genes were RPL5 and UBC with geNorm, and GAPDH and CY with NormFinder. The technical variability analysis with RPL5 and abalone gonad/digestive gland tissue indicated a high repeatability with a variation coefficient within groups ≤ 0.56% and between groups ≤ 1.89%. These results will help us for further research in reproduction, thermoregulation and endocrinology in red abalone. [ABSTRACT FROM AUTHOR]