Integration of Maps Enables a Cytogenomics Analysis of the Complete Karyotype in .

The Pleuronectiformes order, which includes several commercially-important species, has undergone extensive chromosome evolution. One of these species is , a flatfish with 2 = 42 chromosomes. In this study, a cytogenomics approach and integration with previous maps was applied to characterize the karyotype of the species.

Cytogenomics Unveil Possible Transposable Elements Driving Rearrangements in Chromosomes 2 and 4 of .

Cytogenomics, the integration of cytogenetic and genomic data, has been used here to reconstruct the evolution of chromosomes 2 and 4 of . is a flat fish with a karyotype comprising 2n = 42 chromosomes: 6 metacentric + 4 submetacentric + 8 subtelocentric + 24 telocentric. The Fluorescence Hybridization with Bacterial Artificial Chromosomes (FISH-BAC) technique was applied to locate BACs in these chromosomes (11 and 10 BACs in chromosomes 2 and 4, respectively) and to generate integrated maps.

A Comprehensive Integrated Genetic Map of the Complete Karyotype of (Kaup 1858).

aquaculture production has experienced a great increase in the last decade and, consequently, the genome knowledge of the species is gaining attention. In this sense, obtaining a high-density genome mapping of the species could offer clues to the aquaculture improvement in those aspects not resolved so far. In the present article, a review and new processed data have allowed to obtain a high-density BAC-based cytogenetic map of beside the analysis of the sequences of such BAC clones to achieve integrative data.

The genomic structure of the highly-conserved dmrt1 gene in Solea senegalensis (Kaup, 1868) shows an unexpected intragenic duplication.

Knowing the factors responsible for sex determination in a species has significant theoretical and practical implications; the dmrt1 gene (Doublesex and Mab-3 (DM)-related Transcription factor 1) plays this role in diverse animal species. Solea senegalensis is a commercially important flat fish in which females grow 30% faster than males. It has 2n = 42 chromosomes and an XX / XY chromosome system for sex determination, without heteromorph chromosomes but with sex proto-chromosome.

Gene clusters related to metamorphosis in Solea senegalensis are highly conserved.

The flatfish, Solea senegalensis has considerable scientific interest and commercial value. The metamorphosis in this species occurs between 12 and 19 days after hatching and it takes about 1 week to complete. Eleven Bacterial Artificial Chromosomes (BAC) clones containing the various candidate genes involved in the process of metamorphosis: thyroxine 5 deiodinase 3 (dio3); forkhead box protein E4 (foxe4); melatonin receptor type 1C (mel1c); calsequestrin 1b (casq1b); thyrotropin subunit beta (tshβ); thyrotropin-releasing hormone receptor 1, 2, and 3 (trhr1, trhr2, trhr3); thyroid hormone receptor α a and b (thrαa, thrαb); and thyroid hormone receptor beta (thrβ) were analyzed by multiple Fluorescence in situ Hybridization (mFISH) and Next Generation Sequencing (NGS) techniques.

Integrative genetic map of repetitive DNA in the sole Solea senegalensis genome shows a Rex transposon located in a proto-sex chromosome.

Repetitive sequences play an essential role in the structural and functional evolution of the genome, particularly in the sexual chromosomes. The Senegalese sole (Solea senegalensis) is a valuable flatfish in aquaculture albeit few studies have addressed the mapping and characterization of repetitive DNA families. Here we analyzed the Simple Sequence Repeats (SSRs) and Transposable elements (TEs) content from fifty-seven BAC clones (spanning 7.

Evolution of the Proto Sex-Chromosome in .

is a flatfish belonging to the Soleidae family within the Pleuronectiformes order. It has a karyotype of 2 = 42 (FN = 60; 6M + 4 SM + 8 St + 24 T) and a XX/XY system. The first pair of metacentric chromosomes has been proposed as a proto sex-chromosome originated by a Robertsonian fusion between acrocentric chromosomes.

Genome and Phylogenetic Analysis of Genes Involved in the Immune System of - Potential Applications in Aquaculture.

Global aquaculture production continues to increase rapidly. One of the most important species of marine fish currently cultivated in Southern Europe is , reaching more than 300 Tn in 2017. In the present work, 14 Bacterial Artificial Chromosome (BAC) clones containing candidate genes involved in the immune system (, , , , α, , , , , , , , and ), were examined and compared with other species using multicolor Fluorescence Hybridization (mFISH), massive sequencing and bioinformatic analysis to determine the genomic surroundings and syntenic chromosomal conservation of the genomic region contained in each BAC clone.

A preliminary integrated genetic map distinguishes every chromosome pair and locates essential genes related to abiotic adaptation of Crassostrea angulata/gigas.

Background: The re-sequencing of C. angulata has revealed many polymorphisms in candidate genes related to adaptation to abiotic stress that are not present in C. gigas; these genes, therefore, are probably related to the ability of this oyster to retain high concentrations of toxic heavy metals.

Evidence for a Robertsonian fusion in Solea senegalensis (Kaup, 1858) revealed by zoo-FISH and comparative genome analysis.

Background: Solea senegalensis (Kaup, 1858) is a commercially important flatfish species, belonging to the Pleuronectiformes order. The taxonomy of this group has long been controversial, and the karyotype of the order presents a high degree of variability in diploid number, derived from chromosomal rearrangements such as Robertsonian fusions. Previously it has been proposed that the large metacentric chromosome of S.

Analysis of the histone cluster in Senegalese sole (Solea senegalensis): evidence for a divergent evolution of two canonical histone clusters.

The Senegalese sole (Solea senegalensis) is commercially very important and a priority species for aquaculture product diversification. The main histone cluster was identified within two BAC clones. However, two replacement histones (H1.

Evolutionary Dynamics of rDNAs and U2 Small Nuclear DNAs in Triportheus (Characiformes, Triportheidae): High Variability and Particular Syntenic Organization.

Multigene families correspond to a group of genes tandemly repeated, showing enormous diversity in both number of units and genomic organization. In fishes, unlike rDNAs that have been well explored in cytogenetic studies, U2 small nuclear RNA (snRNA) genes are poorly investigated concerning their chromosomal localization. All Triportheus species (Characiformes, Triportheidae) studied so far carry a ZZ/ZW sex chromosomes system, where the W chromosome contains a huge 18S rDNA cistron.

Integrated gene mapping and synteny studies give insights into the evolution of a sex proto-chromosome in Solea senegalensis.

The evolution of genes related to sex and reproduction in fish shows high plasticity and, to date, the sex determination system has only been identified in a few species. Solea senegalensis has 42 chromosomes and an XX/XY chromosome system for sex determination, while related species show the ZZ/ZW system. Next-generation sequencing (NGS), multi-color fluorescence in situ hybridization (mFISH) techniques, and bioinformatics analysis have been carried out, with the objective of revealing new information about sex determination and reproduction in S.

Adaptation to abiotic stress in the oyster Crassostrea angulata relays on genetic polymorphisms.

Here we describe the whole genome re-sequencing of the Portuguese oyster Crassostrea angulata, an edible cupped oyster of major commercial importance with an important role as biosensor of coastal water pollution. We sequenced the genome of the C. angulata to 29.

Sequencing of the core MHC region of black grouse (Tetrao tetrix) and comparative genomics of the galliform MHC.

Background: The MHC, which is regarded as the most polymorphic region in the genomes of jawed vertebrates, plays a central role in the immune system by encoding various proteins involved in the immune response. The chicken MHC-B genomic region has a highly streamlined gene content compared to mammalian MHCs. Its core region includes genes encoding Class I and Class IIB molecules but is only ~92Kb in length.

Genetic characterization of Plectorhinchus mediterraneus yields important clues about genome organization and evolution of multigene families.

Background: Molecular and cytogenetic markers are of great use for to fish characterization, identification, phylogenetics and evolution. Multigene families have proven to be good markers for a better understanding of the variability, organization and evolution of fish species. Three different tandemly-repeated gene families (45S rDNA, 5S rDNA and U2 snDNA) have been studied in Plectorhinchus mediterraneus (Teleostei: Haemulidae), at both molecular and cytogenetic level, to elucidate the taxonomy and evolution of these multigene families, as well as for comparative purposes with other species of the family.