Chromosome mapping of repetitive sequences in four Serrasalmidae species (Characiformes)

Ribeiro, Leila Braga; Matoso, Daniele Aparecida; Feldberg, Eliana

doi:10.1590/s1415-47572014000100009

Cited by 17 publications

(17 citation statements)

References 28 publications

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“…Concerning telomeric sequences, the detection of the vertebrate (TTAGGG) n repeat at chromosome ends in M . merluccius and their absence at intercalary locations is coincident with results obtained in the majority of species of fishes analyzed [ 18 , 23 , 33 , 47 , 48 ].…”

Section: Discussionsupporting

confidence: 89%

Molecular Cytogenetic Analysis of the European Hake Merluccius merluccius (Merlucciidae, Gadiformes): U1 and U2 snRNA Gene Clusters Map to the Same Location

et al. 2015

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The European hake (Merluccius merluccius) is a highly valuable and intensely fished species in which a long-term alive stock has been established in captivity for aquaculture purposes. Due to their huge economic importance, genetic studies on hakes were mostly focused on phylogenetic and phylogeographic aspects; however chromosome numbers are still not described for any of the fifteen species in the genus Merluccius. In this work we report a chromosome number of 2n = 42 and a karyotype composed of three meta/submetacentric and 18 subtelo/telocentric chromosome pairs. Telomeric sequences appear exclusively at both ends of every single chromosome. Concerning rRNA genes, this species show a single 45S rDNA cluster at an intercalary location on the long arm of subtelocentric chromosome pair 12; the single 5S rDNA cluster is also intercalary to the long arm of chromosome pair 4. While U2 snRNA gene clusters map to a single subcentromeric position on chromosome pair 13, U1 snRNA gene clusters seem to appear on almost all chromosome pairs, but showing bigger clusters on pairs 5, 13, 16, 17 and 19. The brightest signals on pair 13 are coincident with the single U2 snRNA gene cluster signals. Therefore, the use of these probes allows the unequivocal identification of at least 7 of the chromosome pairs that compose the karyotype of Merluccius merluccius thus opening the way to integrate molecular genetics and cytological data on the study of the genome of this important species.

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Section: Discussionsupporting

confidence: 89%

Molecular Cytogenetic Analysis of the European Hake Merluccius merluccius (Merlucciidae, Gadiformes): U1 and U2 snRNA Gene Clusters Map to the Same Location

et al. 2015

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“…The distribution of telomeric sequences in the chromosomes provides important insights for the understanding of the evolutionary history of groups or organisms and may indicate the occurrence of chromosomal rearrangements (Ashley and Ward, 1993;Scacchetti et al, 2015). In many fish species, specific sequences revealed by FISH also indicate the presence of interstitial telomeric sites (ITSs) (reviewed in Ocalewicz, 2013;Ribeiro et al, 2014;Scacchetti et al, 2015;Nirchio et al, 2020). Homogeneous signals were observed in the terminal regions of both arms of the chromosomes of H. multifasciatus, and no evidence of the presence of ITSs was found, reinforcing the conserved diploid number of this species.…”

Section: Resultsmentioning

confidence: 99%

Molecular cytogenetic analysis and the establishment of a cell culture in the fish species Hollandichthys multifasciatus (Eigenmann & Norris, 1900) (Characiformes, Characidae)

et al. 2021

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Hollandichthys is a fish genus of the family Characidae that was until recently considered to be monotypic, with cytogenetic, morphological, and molecular data being restricted to a few local populations. In the present study, the karyotype of a population of Hollandichthys multifasciatus was analyzed using classical and molecular cytogenetic approaches for the investigation of potential markers that could provide new perspectives on the cytotaxonomy. H. multifasciatus presented a diploid number of 2n=50 chromosomes and a karyotype formula of 8m+10sm+32st. A single pair of chromosomes presented Ag-NORs signals, which coincided with the 18S rDNA sites visualized by FISH, whilst the 5S rDNA sequences were mapped in two chromosome pairs. The distribution of the U snRNA genes was mapped on the Hollandichthys chromosomes for the first time, with the probes revealing the presence of the U1 snDNA on the chromosomes of pair 20, U2 on pairs 6 and 19, U4 on pair 16, and U6 on the chromosomes of pair 11. The results of the present study indicated karyotypic differences in comparison with the other populations of H. multifasciatus studied previously, reinforcing the need for further research to identify isolated populations or the potential existence of cryptic Hollandichthys species.

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“…Markers were assigned into 27 linkage groups (LGs) (corresponding to the 27 pairs of chromosomes in pacu) by SeparateChromosomes2. In the LG assignment, an optimized LOD score of 8.6 was achieved binning the markers into LGs by adoption of LOD scores ranging from 4 to 15 [56]. The orphan markers were assigned to existing linkage groups (optimized LOD score = 6.7) using JoinSingles2 to maximize the map-abilities of the total input of markers, and ordered the binned markers within linkage groups using OrderMarkers2.…”

Section: Linkage Map and Synteny Analysismentioning

confidence: 99%

Development of a SNP linkage map and genome-wide association study for resistance to Aeromonas hydrophila in pacu (Piaractus mesopotamicus)

et al. 2020

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Background Pacu (Piaractus mesopotamicus) is one of the most important Neotropical aquaculture species from South America. Disease outbreaks caused by Aeromonas hydrophila infection have been considered significant contributors to the declining levels of pacu production. The current implementation of genomic selection for disease resistance has been adopted as a powerful strategy for improvement in fish species. This study aimed to investigate the genetic architecture of resistance to A. hydrophila in pacu via Genome-Wide Association Study (GWAS), the identification of suggestive Quantitative Trait Loci (QTLs) and putative genes associated with this trait. The genetic data were obtained from 381 juvenile individuals belonging to 14 full-sibling families. An experimental challenge was performed to gain access to the levels of genetic variation for resistance against the bacteria using the following trait definitions: binary test survival (TS) and time of death (TD). Results The analyses of genetic parameters estimated moderate heritability (h2) for both resistance traits: 0.20 (± 0.09) for TS and 0.35 (± 0.15) for TD. A linkage map for pacu was developed to enable the GWAS, resulting in 27 linkage groups (LGs) with 17,453 mapped Single Nucleotide Polymorphisms (SNPs). The length of the LGs varied from 79.95 (LG14) to 137.01 (LG1) cM, with a total map length of 2755.60 cM. GWAS identified 22 putative QTLs associated to A. hydrophila resistance. They were distributed into 17 LGs, and were considered suggestive genomic regions explaining > 1% of the additive genetic variance (AGV) for the trait. Several candidate genes related to immune response were located close to the suggestive QTLs, such as tbk1, trim16, Il12rb2 and lyz2. Conclusion This study describes the development of the first medium density linkage map for pacu, which will be used as a framework to study relevant traits to the production of this species. In addition, the resistance to A. hydrophila was found to be moderately heritable but with a polygenic architecture suggesting that genomic selection, instead of marker assisted selection, might be useful for efficiently improving resistance to one of the most problematic diseases that affects the South American aquaculture.

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Chromosome mapping of repetitive sequences in four Serrasalmidae species (Characiformes)

Cited by 17 publications

References 28 publications

Molecular Cytogenetic Analysis of the European Hake Merluccius merluccius (Merlucciidae, Gadiformes): U1 and U2 snRNA Gene Clusters Map to the Same Location

Molecular Cytogenetic Analysis of the European Hake Merluccius merluccius (Merlucciidae, Gadiformes): U1 and U2 snRNA Gene Clusters Map to the Same Location

Molecular cytogenetic analysis and the establishment of a cell culture in the fish species Hollandichthys multifasciatus (Eigenmann & Norris, 1900) (Characiformes, Characidae)

Development of a SNP linkage map and genome-wide association study for resistance to Aeromonas hydrophila in pacu (Piaractus mesopotamicus)

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