Karyotype description of three species of Loricariidae (Siluriformes) and occurrence of the ZZ/ZW sexual system in Hemiancistrus spilomma Cardoso &amp; Lucinda, 2003

Oliveira, Renildo Ribeiro de; Souza, Issakar Lima; Vênere, Paulo César

doi:10.1590/s1679-62252006000100010

Cited by 29 publications

(28 citation statements)

References 13 publications

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“…Loricariidae fish shows a very large variation of the chromosome number as a whole, which ranges from 2n = 80 in a Hypostomus species (Artoni & Bertollo, 1996), to 2n = 34 in Ancistrus species (de Oliveira, 2006;present work). Besides the chromosome number, the karyotypic formula is also variable, showing a differentiated karyotypic evolution throughout the speciation process of this family.…”

Section: Discussionmentioning

confidence: 83%

“…However, as new studies were performed in Ancistrini it was pointed out that the chromosomal diversity go beyond the previously supposition for this group. Indeed, the Ancistrini tribe is characterized by a chromosomal diversification, especially in the genus Ancistrus where distinct karyotypic structures indicate a probable species complex (Mariotto & Miyazawa, 2006), besides the occurrence of simple and multiple sex chromosome systems (Mariotto et al, 2004;Mariotto & Miyazawa, 2006;de Oliveira et al, 2007de Oliveira et al, , 2008, as well as simple or multiple and interstitial or terminal NOR systems (Alves et al, 2003;Mariotto et al, 2004;Souza et al, 2004;Mariotto & Miyazawa, 2006;de Oliveira et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

“…1, Peckoltia sp. 2 (Souza, 2003) and Hemiancistrus spilomma (de Oliveira et al, 2006), may represent a derived characteristic for this group. Loricariidae generally possess little heterochromatin, as also found in A. cuiabae, which seems like an ancestral condition for this group.…”

Section: Discussionmentioning

confidence: 99%

“…1 and Ancistrus sp. 2 in Amazonian rivers (de Oliveira, 2006), to 2n = 52 in Hemiancistrus sp. and Panaque cf.…”

Section: Introductionmentioning

confidence: 98%

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Chromosome polymorphism in Ancistrus cuiabae Knaack, 1999 (Siluriformes: Loricariidae: Ancistrini)

et al. 2009

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Cytogenetic and FISH analyses were performed in 30 Ancistrus cuiabae specimens from a bay near the town of Poconé, in the Pantanal of Mato Grosso, Brazil. The observed diploid number was 2n = 34 chromosomes for both sexes and three distinct katyotypic formulae were found, namely cytotype A (20m, 8sm, 6st, Fundamental Number/FN = 68; 6 males and 11 females), cytotype B (19m, 8sm, 6st, 1a, FN = 67; 8 males and 4 females) and cytotype C (18m, 8sm, 6st, 2a, FN = 66; a single male). NORs's analyses showed that these regions were located in distinct sites on the NOR-bearing chromosome pair, according to cytotypes. Thus, in cytotype A, NORs were located in the terminal region of the short arm of the second metacentric chromosome pair; in cytotype B, they were detected in the short arm of the metacentric chromosome and interstitially on the acrocentric chromosome and, in cytotype C, NORs were observed in the interstitial region of the acrocentric chromosome pair. C-positive heterochromatic bands were adjacent to the rDNA sites in the corresponding chromosomes. Thus, the chromosomal polymorphism of A. cuiabae was probably originated through a pericentric inversion in chromosome pair nº 2 involving the NOR sites, which represents a novelty in the Ancistrini tribe. The results also broaden the knowledge of the chromosomal evolution in Ancistrus, the most derived genus of the Ancistrini tribe.Foram analisados, com técnicas convencionais de citogenética e FISH, 30 exemplares da espécie Ancistrus cuiabae da baía Arrombado, próximo a Poconé, Pantanal do Mato Grosso. Foram observadas metáfases com número diploide 2n = 34 cromossomos para ambos os sexos e três fórmulas cariotípicas distintas, aqui denominadas de citótipo A, verificado em 06 machos e 11 fêmeas (20m, 8sm, 6st, Número Fundamental, NF = 68); citótipo B, em 08 machos e 04 fêmeas (19m, 8sm, 6st, 1a, NF = 67) e citótipo C em apenas 01 macho (18m, 8sm, 6st, 2a, NF = 66). As NORs confirmaram os distintos citótipos verificados, além de evidenciar que os cromossomos portadores de rDNA são os que representam o polimorfismo na espécie Ancistrus cuiabae. No citótipo A, as NORs foram verificadas na região terminal do braço curto do segundo par de cromossomos metacêntricos; no citótipo B, foram evidenciadas no segundo par, heteromórfico, no braço curto do cromossomo metacêntrico e intersticial no seu homólogo acrocêntrico; no citótipo C as NORs foram observadas na região intersticial num par de cromossomos acrocêntricos. A análise da heterocromatina constitutiva evidenciou blocos discretos adjacentes ao rDNA no segundo par de cromossomos de ambos os citótipos. Uma provável inversão pericêntrica é a hipótese proposta para a origem deste polimorfismo na espécie Ancistrus cuiabae. Estes resultados ampliam o conhecimento sobre o gênero Ancistrus, o mais derivado da tribo, contribuem para o conhecimento sobre este grupo de peixes e para inferir sobre a evolução cromossômica dos Ancistrini.

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Section: Discussionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…1 and Ancistrus sp. 2 in Amazonian rivers (de Oliveira, 2006), to 2n = 52 in Hemiancistrus sp. and Panaque cf.…”

Section: Introductionmentioning

confidence: 98%

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Chromosome polymorphism in Ancistrus cuiabae Knaack, 1999 (Siluriformes: Loricariidae: Ancistrini)

et al. 2009

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“…According to Alves et al (2003) and de Oliveira (2006), centric fusions are the main chromosomal rearrangement within Ancistrus, in which the reduction of diploid number seems to be an evolutionary trend. Nonetheless, other rearrangements, such as pericentric inversions and heterochromatin accumulation are also important for the chromosomal diversification and karyotype evolution of loricarids.…”

Section: Introductionmentioning

confidence: 99%

Diversity and chromosomal evolution in the genus Ancistrus Kner, 1854 (Loricariidae: Ancistrini) from three hydrographic basins of Mato Grosso State, Brazil

2013

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Cytogenetic analyses were carried out in 117 specimens of seven species of the genus Ancistrus from three hydrographic in Mato Grosso State: Paraguay, Araguaia-Tocantins and Amazon basins. Conventional cytogenetic techniques were used to obtain mitotic chromosomes. C-banding was performed to detect heterochromatic regions and silver nitrate staining was used to identify nucleolar organizer regions (Ag-NORs). The counted and paired chromosomes revealed diploid numbers ranging from 2n = 40 to 2n = 54 with karyotype formulae varying from FN = 80 to FN = 86. Single marks in distinct chromosomes identified the nucleolar organizer regions. The constitutive heterochromatin was scarce in the diploid number from 2n = 50 to 2n = 54 and conspicuous blocks were observed in a single species with 2n = 40 chromosomes. These data corroborate the hypotheses of reduction of diploid number in species with derived features such as presence of sex chromosomes and polymorphisms, besides allowing inferences about the evolutionary mechanisms and the ancestor karyotype that favored the diversification of this important genus in the tribe Ancistrini. Foram realizadas análises citogenéticas de 117 espécimes do gênero Ancistrus de três bacias hidrográficas do estado de MatoGrosso: Paraguai, Araguaia-Tocantins e Amazônica, utilizando as técnicas de citogenética convencional para obtenção de cromossomos mitóticos, visualização de regiões heterocromáticas e regiões organizadoras de nucléolos. Os cromossomos pareados revelaram uma variação no número diploide de 2n = 40 a 2n = 54 e número fundamental de NF = 80 a NF = 86. As regiões organizadoras de nucléolos foram evidenciadas em um único par de cromossomos para todas as espécies e a heterocromatina é escassa nas espécies com números diploides elevados (2n = 50 a 2n = 54). Os blocos heterocromáticos mais evidentes foram observados nos pares portadores das AgRONs e em cromossomos da espécie com 2n = 40. Estes dados contribuem para a hipótese de redução do número diploide nas espécies que apresentam polimorfismos cromossômicos e cromossomos sexuais, além de contribuir para inferências sobre os mecanismos de evolução cariotípica que favoreceu a diversificação do gênero Ancistrus, o mais representativo na tribo Ancistrini.

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Occurrence of multiple sexual chromosomes (XX/XY1Y2 and Z1Z1Z2Z2/Z1Z2W1W2) in catfishes of the genus Ancistrus (Siluriformes: Loricariidae) from the Amazon basin

et al. 2007

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Loricariid catfishes show a predominance of homomorphism in sex chromosomes, but cases of simple and multiple systems were also found. Here we describe two cases of multiple sex chromosome systems in loricariids from Brazilian Amazonia. Males of Ancistrus sp.1 "Balbina" have a modal number of 2n = 39 chromosomes, fundamental number (FN) of 78, and karyotypic formula of 27 m + 10 sm + 2 st; females have 2n = 38 chromosomes, FN = 76, and 26 m + 10 sm + 2 st. Ancistrus sp.2 "Barcelos" has 2n = 52 chromosomes for both sexes, FN = 80 for males and FN = 79 for females. Karyotypic formula is 12 m + 12 sm + 4 st + 24a for males and 11 m + 12 sm + 4st + 25a for females. The two species show different arrangements of constitutive heterochromatin blocks, which are coincident with NORs and absent in sex chromosomes. We suggest a XX/XY(1)Y(2) mechanism for Ancistrus sp.1 "Balbina", and a Z(1)Z(1)Z(2)Z(2)/Z(1)Z(2)W(1)W(2) mechanism for Ancistrus sp.2 "Barcelos". The XX/XY(1)Y(2) mechanism here reported is the second known occurrence of this type of multiple sex chromosomes for Loricariidae and the third for Neotropical fishes; the mechanism Z(1)Z(1)Z(2)Z(2)/Z(1)Z(2)W(1)W(2) represents the first record among fishes. The presence of different sex chromosome systems in Ancistrus indicates a probable independent origin and suggests that the differentiation of sex chromosomes is evolutionarily recent among species in this genus.

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Karyotype description of three species of Loricariidae (Siluriformes) and occurrence of the ZZ/ZW sexual system in Hemiancistrus spilomma Cardoso & Lucinda, 2003

Cited by 29 publications

References 13 publications

Chromosome polymorphism in Ancistrus cuiabae Knaack, 1999 (Siluriformes: Loricariidae: Ancistrini)

Chromosome polymorphism in Ancistrus cuiabae Knaack, 1999 (Siluriformes: Loricariidae: Ancistrini)

Diversity and chromosomal evolution in the genus Ancistrus Kner, 1854 (Loricariidae: Ancistrini) from three hydrographic basins of Mato Grosso State, Brazil

Occurrence of multiple sexual chromosomes (XX/XY1Y2 and Z1Z1Z2Z2/Z1Z2W1W2) in catfishes of the genus Ancistrus (Siluriformes: Loricariidae) from the Amazon basin

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