Characterization of the myostatin gene in the neotropical species Piaractus mesopotamicus and the possibility of its use in genetic improvement programs.

Background: The myostatin gene has played an important role in the genetic improvement of the main species of economic importance; however, it has not yet been described for some Neotropical fish essential for aquaculture. This study aimed to characterize the myostatin gene of pacu, Piaractus mesopotamicus, and investigate the association of a microsatellite marker in this gene with the weight of fish.

Methods And Results: The myostatin gene sequence was obtained after following a RACE-PCR strategy based on a partial mRNA sequence available in the GenBank database and the alignment of myostatin sequences from other fish species.

The Satellite DNA Catalogues of Two Serrasalmidae (Teleostei, Characiformes): Conservation of General satDNA Features over 30 Million Years.

Satellite DNAs (satDNAs) are tandemly repeated sequences that are usually located on the heterochromatin, and the entire collection of satDNAs within a genome is called satellitome. Primarily, these sequences are not under selective pressure and evolve by concerted evolution, resulting in elevated rates of divergence between the satDNA profiles of reproductive isolated species/populations. Here, we characterized two additional satellitomes of Characiformes fish ( and ) that diverged approximately 30 million years ago, while still retaining conserved karyotype features.

Genomic selection signatures in farmed from tropical and subtropical regions in South America.

Tambaqui or cachama () is one of the most important neotropical freshwater fish used for aquaculture in South America, and its production is concentrated at low latitudes (close to the Equator, 0°), where the water temperature is warm. Therefore, understanding how selection shapes genetic variations and structure in farmed populations is of paramount importance in evolutionary biology. High-throughput sequencing to generate genome-wide data for fish species allows for elucidating the genomic basis of adaptation to local or farmed conditions and uncovering genes that control the phenotypes of interest.

Use of Molecular Genetic Methods to Reduce the Risk of Incorrect Identification of Fish Strains in Brazilian Aquaculture.

The identification of fish species using traditional methods is generally based only on morphological characteristics and these methods are currently under review. This kind of identification of hybrid fishes solely based on their morphologies may be unreliable, especially when the samples include juveniles and post-F1 lineage fishes. Therefore, in the present study, we used molecular markers to accurately identify the fish species of economic interest that are used as materials in the projects developed in research institutions.

Sex-Dependent Inheritance of B Chromosomes in (Teleostei, Characiformes) Revealed by Directed Crossings.

B chromosomes are additional dispensable elements to the standard chromosomal set of an organism. In most cases, their transmission differs from Mendelian patterns, leading to their accumulation or extinction. The present study aimed to describe, for the first time, the transmission pattern of B chromosome in a population of through directed crosses, as well as to analyze the populational dynamics of B chromosome.

ETosis in tambaqui Colossoma macropomum: A programmed cell death pathway and approach of leukocytes immune response.

Tambaqui Colossoma macropomum is the most cultivated native fish in South America and Aeromonas hydrophila is one of the main bacteria infecting tropical fish. Despite the economic importance of this round fish, to date, there has been a paucity of investigations into haematological changes in tambaqui. In this study, detailed blood analyses (0 h, 6 h, 24 h, 7 d and 14 d) following intraperitoneal challenge with A.

Corrigenda: Cytogenetic markers as a tool for characterization of hybrids of Baird & Girard, 1854 and Eigenmann, 1907. Comparative Cytogenetics 14(2): 231-242. https://doi.org/10.3897/CompCytogen.v14i2.49513.

[This corrects the article DOI: 10.3897/CompCytogen.v14i2.

Patterns of the innate immune response in tambaqui Colossoma macropomum: Modulation of gene expression in haemorrhagic septicaemia caused by Aeromonas hydrophila.

The production of tambaqui Colossoma macropomum has recently reached a milestone, being considered the main native species produced in South American continental waters. Despite the importance of this fish, its immunity is not well understood. In this study we established some patterns of innate immunity for the species via two experiments.

Motile Aeromonas septicemia in tambaqui Colossoma macropomum: Pathogenicity, lethality and new insights for control and disinfection in aquaculture.

Tambaqui Colossoma macropomum is the most produced native fish in South America. Besides the lack of knowledge regarding bacteria-stricken diseases, the unappropriated using of off-label therapies are common. In this study, Aeromonas hydrophila pathogenicity for tambaqui was first established by Koch's Postulate.

Transcriptome Profiling of Pacu () Challenged With Pathogenic : Inference on Immune Gene Response.

Pacu () is a Neotropical fish of major importance for South American aquaculture. Septicemia caused by bacteria is currently considered a substantial threat for pacu aquaculture that have provoked infectious disease outbreaks with high economic losses. The understanding of molecular aspects on progress of infection and pacu immune response is scarce, which have limited the development of genomic selection for resistance to this infection.

Cytogenetic markers as a tool for characterization of hybrids of Baird & Girard, 1854 and Eigenmann, 1907.

Baird et Girard, 1854, is one of the largest genera in the family Characidae and comprises 177 valid species. This genus has been the focus of cytogenetic studies primarily owing to the presence of B chromosomes and high karyotypic diversity among different populations. The intense genetic variability in is one of the factors responsible for the occurrence of species complexes, which are groups (1) with certain difficulties in establishing common genetic pools or (2) belonging to different cryptic species.

Publisher Correction: High-throughput analysis unveils a highly shared satellite DNA library among three species of fish genus Astyanax.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Assessing Genetic Diversity for a Pre-Breeding Program in by SNPs and SSRs.

The pacu () is a Neotropical fish with remarkable productive performance for aquaculture. Knowledge of genetic resources in Neotropical fish is essential for their applications in breeding programs. The aim of this study was to characterize the genetic diversity of seven farmed populations of pacu which will constitute the basis for a broodstock foundation for coming breeding programs in Brazil.

Satellitome landscape analysis of Megaleporinus macrocephalus (Teleostei, Anostomidae) reveals intense accumulation of satellite sequences on the heteromorphic sex chromosome.

The accumulation of repetitive DNA sequences on the sex-limited W or Y chromosomes is a well-known process that is likely triggered by the suppression of recombination between the sex chromosomes, which leads to major differences in their sizes and genetic content. Here, we report an analysis conducted on the satellitome of Megaleporinus macrocephalus that focuses specifically on the satDNAs that have been shown to have higher abundances in females and are putatively located on the W chromosome in this species. We characterized 164 satellite families in M.

High-throughput analysis unveils a highly shared satellite DNA library among three species of fish genus Astyanax.

The high-throughput analysis of satellite DNA (satDNA) content, by means of Illumina sequencing, unveiled 45 satDNA families in the genome of Astyanax paranae, with repeat unit length (RUL) ranging from 6 to 365 bp and marked predominance of short satellites (median length = 59 bp). The analysis of chromosomal location of 35 satDNAs in A. paranae, A.

Origin of B chromosomes in the genus Astyanax (Characiformes, Characidae) and the limits of chromosome painting.

Eukaryote genomes are frequently burdened with the presence of supernumerary (B) chromosomes. Their origin is frequently investigated by chromosome painting, under the hypothesis that sharing the repetitive DNA sequences contained in the painting probes is a sign of common descent. However, the intragenomic mobility of many anonymous DNA sequences contained in these probes (e.

Uncovering the Ancestry of B Chromosomes in Moenkhausia sanctaefilomenae (Teleostei, Characidae).

B chromosomes constitute a heterogeneous mixture of genomic parasites that are sometimes derived intraspecifically from the standard genome of the host species, but result from interspecific hybridization in other cases. The mode of origin determines the DNA content, with the B chromosomes showing high similarity with the A genome in the first case, but presenting higher similarity with a different species in the second. The characid fish Moenkhausia sanctaefilomenae harbours highly invasive B chromosomes, which are present in all populations analyzed to date in the Parana and Tietê rivers.

First Description of supernumerary Chromosomes in Ictaluruspunctatus Rafinesque 1818 Reveals Active Ribosomal Genes in the B Complement.

The North American channel catfish Ictalurus punctatus Rafinesque 1818 is cultivated in the United States, Asia and Brazilian fish farms, and also utilized as a model species in aquaculture and genetic studies. In this work, cytogenetic analysis of . punctatus from Brazilian aquaculture revealed for the first time the presence of extra elements (supernumerary or B chromosomes) in this species.

New insights into karyotypic relationships among populations of Astyanax bockmanni (Teleostei, Characiformes) of different watersheds.

The fish constitute about 50% of all vertebrates, including a wide morphological and biological diversity, where the genus Astyanax is the most common and diverse, as described in virtually all freshwater environments. By occupying a basal position in the phylogeny of vertebrates, fish are an extremely favorable group for cytogenetic and evolutionary studies. The karyotype found in genus Astyanax diversity may involve a number of polymorphisms, which may be related to ploidy and karyotypic macrostructure, presence of B chromosomes, heterochromatin polymorphisms, and location of ribosomal genes.

Delimiting the origin of a B chromosome by FISH mapping, chromosome painting and DNA sequence analysis in Astyanax paranae (Teleostei, Characiformes).

Supernumerary (B) chromosomes have been shown to contain a wide variety of repetitive sequences. For this reason, fluorescent in situ hybridisation (FISH) is a useful tool for ascertaining the origin of these genomic elements, especially when combined with painting from microdissected B chromosomes. In order to investigate the origin of B chromosomes in the fish species Astyanax paranae, these two approaches were used along with PCR amplification of specific DNA sequences obtained from the B chromosomes and its comparison with those residing in the A chromosomes.

Genetic identification of F1 and post-F1 serrasalmid juvenile hybrids in Brazilian aquaculture.

Juvenile fish trade monitoring is an important task on Brazilian fish farms. However, the identification of juvenile fish through morphological analysis is not feasible, particularly between interspecific hybrids and pure species individuals, making the monitoring of these individuals difficult. Hybrids can be erroneously identified as pure species in breeding facilities, which might reduce production on farms and negatively affect native populations due to escapes or stocking practices.

Chromosomal organization of repetitive DNA sequences in Astyanax bockmanni (Teleostei, Characiformes): dispersive location, association and co-localization in the genome.

Repetitive DNA sequences constitute a great portion of the genome of eukaryotes and are considered key components to comprehend evolutionary mechanisms and karyotypic differentiation. Aiming to contribute to the knowledge of chromosome structure and organization of some repetitive DNA classes in the fish genome, chromosomes of two allopatric populations of Astyanax bockmanni were analyzed using classic cytogenetics techniques and fluorescent in situ hybridization, with probes for ribosomal DNA sequences, histone DNA and transposable elements. These Astyanax populations showed the same diploid number (2n = 50), however with differences in chromosome morphology, distribution of constitutive heterochromatin, and location of 18S rDNA and retroelement Rex3 sites.