B chromosome polymorphism in South American cichlid

Perazzo, Giselle Xavier; Noleto, Rafael Bueno; Vicari, Marcelo Ricardo; Gava, Adriana; Cestari, Marta Margarete

doi:10.1080/23766808.2018.1429164

Cited by 7 publications

(5 citation statements)

References 44 publications

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“…Blocks of high sequence coverage have been described previously in cichlid genomic data when B chromosomes were present, such as in Astatotilapia latifasciata [ 63 , 72 ], Metriaclima lombardoi from Lake Malawi [ 26 ], and the South American cichlid Crenicichla lepidota [ 73 ]. In these studies, high coverage regions were due to A chromosome fragments copied onto a B chromosome, where they are highly amplified and highly polymorphic.…”

Section: Discussionmentioning

confidence: 99%

Structure and Sequence of the Sex Determining Locus in Two Wild Populations of Nile Tilapia

Triay

Conte

Baroiller

et al. 2020

Genes

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In domesticated strains of the Nile tilapia, phenotypic sex has been linked to genetic variants on linkage groups 1, 20 and 23. This diversity of sex-loci might reflect a naturally polymorphic sex determination system in Nile tilapia, or it might be an artefact arising from the process of domestication. Here, we searched for sex-determiners in wild populations from Kpandu, Lake Volta (Ghana-West Africa), and from Lake Koka (Ethiopia-East Africa) that have not been subjected to any genetic manipulation. We analysed lab-reared families using double-digest Restriction Associated DNA sequencing (ddRAD) and analysed wild-caught males and females with pooled whole-genome sequencing (WGS). Strong sex-linked signals were found on LG23 in both populations, and sex-linked signals with LG3 were observed in Kpandu samples. WGS uncovered blocks of high sequence coverage, suggesting the presence of B chromosomes. We confirmed the existence of a tandem amh duplication in LG23 in both populations and determined its breakpoints between the oaz1 and dot1l genes. We found two common deletions of ~5 kb in males and confirmed the presence of both amhY and amh∆Y genes. Males from Lake Koka lack both the previously reported 234 bp deletion and the 5 bp frameshift-insertion that creates a premature stop codon in amh∆Y.

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Section: Discussionmentioning

confidence: 99%

Structure and Sequence of the Sex Determining Locus in Two Wild Populations of Nile Tilapia

Triay

Conte

Baroiller

et al. 2020

Genes

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“…In contrast to other species, A. elizabethae harbors a small B chromosome in one individual. B chromosomes usually arise from the normal complement of the species [61] and have been documented for more than 20 South American cichlid species, in which micro or small chromosomes are predominant [62]. In A. elizabethae, its occurrence is likely associated with the numerical and structural chromosome changes, including asynchronous fusion rearrangements.…”

Section: Discussionmentioning

confidence: 99%

Extensive Chromosomal Reorganization in Apistogramma Fishes (Cichlidae, Cichlinae) Fits the Complex Evolutionary Diversification of the Genus

Costa

Cioffi

Liehr

et al. 2019

IJMS

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Neotropical cichlid fishes are one of the most diversified and evolutionarily successful species assemblages. Extremely similar forms and intraspecific polychromatism present challenges for the taxonomy of some of these groups. Several species complexes have a largely unknown origin and unresolved evolutionary processes. Dwarf cichlids of the genus Apistogramma, comprising more than a hundred species, exhibit intricate taxonomic and biogeographic patterns, with both allopatric and sympatric distributions. However, karyotype evolution and the role of chromosomal changes in Apistogramma are still unknown. In the present study, nine South American Apistogramma species were analyzed using conventional cytogenetic methods and the mapping of repetitive DNA sequences [18S rDNA, 5S rDNA, and (TTAGGG)n] by fluorescence in situ hybridization (FISH). Our results showed that Apistogramma has unique cytogenetic characteristics in relation to closely related groups, such as a reduced 2n and a large number of bi-armed chromosomes. Interspecific patterns revealed a scenario of remarkable karyotypic changes, including a reduction of 2n, the occurrence of B-chromosomes and evolutionary dynamic of rDNA tandem repeats. In addition to the well-known pre-zygotic reproductive isolation, the karyotype reorganization in the genus suggests that chromosomal changes could act as postzygotic barriers in areas where Apistogramma congeners overlap.

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“…The scenario that B chromosomes arose from chromosome rearrangements followed by amplification of DNA sequences has been proposed for some plant species as the result of allopolyploidization [15,31]. A similar scenario, the origin of B chromosomes due to chromosome breaks but due to environmental pollution, has been proposed in studies of cichlids [18,51]. Pollution usually has obvious and severe negative effects on chromosomes.…”

Section: B Chromosomesmentioning

confidence: 90%

Chromosome analysis and the occurrence of B chromosomes in fish parasite Acanthocephalus anguillae (Palaeacanthocephala: Echinorhynchida)

Orosová,

Marková,

Zrzavá

et al. 2023

Parasite

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The cytogenetics of Acanthocephala is a neglected area in the study of this group of endoparasites. Chromosome number and/or karyotypes are known for only 12 of the 1,270 described species, and molecular cytogenetic data are limited to rDNA mapping in two species. The standard karyological technique and mapping of 18S rRNA and H3 histone genes on the chromosomes of Acanthocephalus anguillae individuals from three populations, one of which originated from the unfavorable environmental conditions of the Zemplínska Šírava reservoir in eastern Slovakia, were applied for the first time. All specimens had 2n = 7/8 (male/female); n = 1m + 1m-sm + 1a + 1a (X). Fluorescence in situ hybridization (FISH) revealed three loci of 18S rDNA on two autosomes and dispersion of H3 histone genes on all autosomes and the X chromosome. In addition to the standard A chromosome set, 34% of specimens from Zemplínska Šírava possessed a small acrocentric B chromosome, which was always found to be univalent, with no pairing observed between the B chromosome and the A complement. The B chromosome had a small amount of heterochromatin in the centromeric and telomeric regions of the chromosomal arms and showed two clusters of H3 genes. It is well known that an environment permanently polluted with chemicals leads to an increased incidence of chromosomal rearrangements. As a possible scenario for the B chromosome origin, we propose chromosomal breaks due to the mutagenic effect of pollutants in the aquatic environment. The results are discussed in comparison with previous chromosome data from Echinorhynchida species.

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B chromosome polymorphism in South American cichlid

Cited by 7 publications

References 44 publications

Structure and Sequence of the Sex Determining Locus in Two Wild Populations of Nile Tilapia

Structure and Sequence of the Sex Determining Locus in Two Wild Populations of Nile Tilapia

Extensive Chromosomal Reorganization in Apistogramma Fishes (Cichlidae, Cichlinae) Fits the Complex Evolutionary Diversification of the Genus

Chromosome analysis and the occurrence of B chromosomes in fish parasite Acanthocephalus anguillae (Palaeacanthocephala: Echinorhynchida)

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