Cytogenetic and DNA content in six genera of the family Callichthyidae (Pisces, Siluriformes)

Oliveira, Cláudio; Almeida-Toledo, Lurdes Foresti de; Mori, Lyria; Toledo-Filho, S.A.

doi:10.1080/00087114.1993.10797258

Cited by 31 publications

(44 citation statements)

References 16 publications

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“…79 Variation in the heterochromatin pattern is common within Callichthyidae, given the occurrence of heterochromatin dispersion and amplification events within the group. 80 In tamoatá stronger staining of C-band was observed in individuals collected from polluted environments (the Mindu and Quarenta streams). The increase in heterochromatin suggests a heterochromatinization process or the addition of heterochromatin.…”

Section: Discussionmentioning

confidence: 97%

Genomic Organization Under Different Environmental Conditions:Hoplosternum Littoraleas a Model

et al. 2016

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The Amazon has abundant rivers, streams, and floodplains in both polluted and nonpolluted environments, which show great adaptability. Thus, the goal of this study was to map repetitive DNA sequences in both mitotic chromosomes and erythrocyte micronuclei of tamoatás from polluted and nonpolluted environments and to assess the possible genotoxic effects of these environments. Individuals were collected in Manaus, Amazonas (AM), and submitted to classical and molecular cytogenetic techniques, as well as to a blood micronucleus test. Diploid number equal to 60 chromosomes are present in all individuals, with 18S ribosomal DNA sites present in one chromosome pair and no interstitial telomeric sites on chromosomes. The micronucleus test showed no significant differences in pairwise comparisons between environments or collection sites, but the Rex3 retroelement was dispersed on the chromosomes of individuals from unpolluted environments and compartmentalized in individuals from polluted environments. Divergent numbers of 5S rDNA sites are present in individuals from unpolluted and polluted environments. The mapping of repetitive sequences revealed that micronuclei have different compositions both intra-and interindividually that suggests different regions are lost in the formation of micronuclei, and no single fragile region undergoes breaks, although repetitive DNA elements are involved in this process.

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Section: Discussionmentioning

confidence: 97%

Genomic Organization Under Different Environmental Conditions:Hoplosternum Littoraleas a Model

et al. 2016

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“…Especially among the siluriforms, cases of simple NORs (one pair only) have been recorded, as well as in some Pimelodidae (Dias & Foresti, 1993;Fenocchio, 1993;Fenocchio & Bertollo, 1992a), Ageneiosidae (Fenocchio & Bertollo, 1992b) and in Doradidae species . On the other hand, a few cases are more heterogeneous, with species presenting one or more NOR pairs (multiple NORs), as in the case of some Callichythiidae (Oliveira et al, 1988;Oliveira, 1991;Porto & Feldberg, 1992) and Loricariidae species (Artoni & Bertollo, 2001). …”

Section: Discussionmentioning

confidence: 99%

Cytogenetics of two sympatric Corydoras species (pisces, siluriformes, challichtyidae) of Southern Brazil

et al. 2006

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Karyotypic data are presented for two sympatric Corydoras species of the Lagoa Dourada, namely, C. ehrhadti and C. paleatus, which are found in the upper Tibagi river basin (Ponta Grossa, State of Paraná, Brazil). The same diploid number and karyotypic formula were observed in both species/populations. A great similarity in the constitutive heterochromatin distribution and in the activity of nucleolar organizer regions was also found. The use of in situ hybridization with a fluorescent 18S rDNA probe allowed for the identification of the species/populations through the location of ribosomal sites.Keywords: karyotype, sympatry, heterochromatin, NORs, rDNA. RESUMO Citogenética de espécies simpátricas de Corydoras (pisces, siluriformes, challichtyidae) do Sul do BrasilDados cariotípicos são apresentados para duas espécies simpátricas de Corydoras da Lagoa Dourada, C. ehrhadti e C. paleatus, pertencentes à bacia do alto Rio Tibagi (Ponta Grossa, Paraná, Brasil). O mesmo número diplóide e fórmula cariotípica foram observados em ambas espécies/populações. Grande similaridade foi verificada também para a distribuição da heterocromatina constitutiva e atividade das regiões organizadoras de nucléolos. O emprego da hibridação in situ com sonda fluorescente de DNAr 18S possibilitou identificar as espécies/populações por meio da localização dos sítios ribossomais. simpatria, heterocromatina, RONs, DNAr. 192 ARTONI, R. F. et al. Palavras

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“…Polyploidy is believed to be an important mechanism in the chromosome evolution in some fish groups, such as Catostomidae and Salmonidae (reviewed in Comber and Smith, 2004) or in the neotropical Siluriformes, as Corydoras, Aspidoras and Brochis (Oliveira et al, 1993). Therefore, the polyploidy is particularly propitious to the evolutionary failure in species with differentiated sex chromosomes, likely due to a gene imbalance (Müller, 1925;Svartman et al, 2005).…”

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Natural triploidy in Leporinus cf. elongatus bearing sex chromosomes

2007

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Although several cases of natural triploidy in fish have already been described, spontaneous polyploidy in species with differentiated sex chromosomes are rare. We report the occurrence of a triploid fish (3n = 81) Leporinus cf. elongatus, a species characterized by a highly differentiated ZZ/ZW sex chromosome system, from the São Francisco river. The occurrence of a ZZZ triploid adult indicates the viability of this chromosome constitution in this fish.Key words: polyploidy, triploid fish, ZW chromosomes, sex chromosomes, Anostomidae. The family Anostomidae is composed of 12 genera, constituting a group relatively rich in species, distributed from South to Central America (Garavello, 1979). Eight species from this group, all from the genus Leporinus, exhibit a ZZ/ZW sex chromosome system with marked structural modifications between the sex chromosomes (Galetti et al., 1995;Venere et al., 2004; Molina and Galetti, 2006). The ZW chromosomes of these species point a monophyletic origin, apparently differentiated through processes of heterochromatinization (Galetti and Foresti, 1986;1987). Leporinus is one of the more complexes groups among Characiformes and the largest in number of species, with 87 already described. Several attempts to subdivide it into additional genera and subgenera have failed (Garavello and Britski, 2003).A diploid number of 2n = 54 is common among Leporinus species (Galetti et al., 1995) and no chromosome number variation has been reported in this genus thus far, despite of several reports of natural triploidy in different neotropical fish families (Characidae, Morelli et al., 1983;Fauaz et al., 1994;Centofante et al. 2001; Sternopygidae, Almeida-Toledo et al., 1985; Curimatidae, Venere and Galetti, 1985; Erythrinidae, Giuliano-Caetano and Bertollo, 1990; Thricomycteridae, Borin et al., 2002).This study reports a case of spontaneous natural triploidy in Leporinus cf. elongatus with a highly differentiated ZZ/ZW sex chromosome system. A total of 28 specimens of Leporinus cf. elongatus (12 males and 16 females) collected in the São Francisco river (Três Marias municipality; Brazil) were cytogenetically analyzed through the air-drying technique (Bertollo et al., 1978;Gold et al., 1990). the chromosome preparations were submitted to Ag-NOR (Howell and Black, 1980) and mithramycin staining (Schweizer, 1980). Our results confirmed the previously reported 2n = 54 with a highly differentiated ZZ/ZW sex chromosome system, characterized by a large subtelocentric W chromosome and a submetacentric Z (Molina et al., 1998).A young triploid male with 2n = 3x = 81 and presenting three copies of the Z chromosome was detected ( Figure 1a, b). A previously reported conspicuous mithramycin positive heterochromatic block on the long arm of the Z chromosomes (Molina et al., 1998) was evident in the three Z chromosomes of the triploid complement (Figure 1c). No morphological differences were observed between the triploid and the diploid specimens.The nucleolus organizer regions (NORs) were located near ...

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Cytogenetic and DNA content in six genera of the family Callichthyidae (Pisces, Siluriformes)

Cited by 31 publications

References 16 publications

Genomic Organization Under Different Environmental Conditions:Hoplosternum Littoraleas a Model

Genomic Organization Under Different Environmental Conditions:Hoplosternum Littoraleas a Model

Cytogenetics of two sympatric Corydoras species (pisces, siluriformes, challichtyidae) of Southern Brazil

Natural triploidy in Leporinus cf. elongatus bearing sex chromosomes

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