A Monophyletic ZW Sex Chromosome System in Leporinus (Anostomidae, Characiformes).

Galetti, Pedro Manoel; Lima, Neuza Rejane Wille; Vênere, Paulo César

doi:10.1508/cytologia.60.375

Cited by 60 publications

(49 citation statements)

References 23 publications

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“…The presence of 2n=54 biarmed chromosomes have also been consistently found in the families Anostomidae (Galetti Jr et al, 1991a, 1991bGaletti Jr et al, 1995), Curimatidae (Vênere & Galetti, 1989;Feldberg et al, 1992;Navarrete & Júlio, 1997), and Chilodontidae (Cestari et al, 1990;Vênere, 1998), corroborating the hypothesis that these four families constitute a natural group in the order Characiformes (Vari, 1983).…”

Section: Fig 1 Karyotypes Of: A) Prochilodus Mariae With 2n=54 Chrosupporting

confidence: 53%

“…The same was reported to occur in other Prochilodus species (Pauls & Bertollo, 1990), showing that this characteristic is very much conserved in the genus. The remarkable conservatism of the Ag-NOR-bearing chromosome pair in Prochilodus species is noteworthy considering that even the species of Curimatidae (Vênere & Galetti, 1989;Feldberg et al, 1992;Navarrete & Júlio, 1997) and Anostomidae (Galetti Jr et al, 1991a, 1991bGaletti Jr et al, 1995) that have very conservative karyotypes, usually display speciesspecific Ag-NOR-bearing chromosomes. The karyotype of P. mariae showed a large amount of heterochromatin, basically in the centromeric and pericentromeric regions of almost all chromosomes (Fig.…”

Section: Fig 1 Karyotypes Of: A) Prochilodus Mariae With 2n=54 Chromentioning

confidence: 99%

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Karyotypic characterization of Prochilodus mariae, Semaprochilodus kneri and S. laticeps(Teleostei: Prochilodontidae) from Caicara del Orinoco, Venezuela

et al. 2003

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Fish of the family Prochilodontidae are considered one of the most important components of commercial and subsistence fishery in freshwater environments in South America. This family consists of 21 species and three genera. In the present study, the karyotypes of Prochilodus mariae, Semaprochilodus kneri, and S. laticeps from Caicara del Orinoco, Bolivar State, Venezuela were studied. The species P. mariae, S. kneri and S. laticeps exhibited 2n=54 chromosomes (40 metacentric and 14 submetacentric), a single chromosome pair with nucleolus organizer regions, and a large amount of heterochromatin found at centromeric and pericentromeric positions in almost all chromosomes. The P. mariae specimens studied displayed 0 to 3 supernumerary microchromosomes. The data obtained here confirm the conservative nature of the chromosome number and morphology of Prochilodontidae and reinforce the hypothesis that small structural chromosome rearrangements were the main cause of the karyotypic diversification seen in this group.Os peixes da família Prochilodontidae são considerados um dos componentes mais importantes da pesca comercial e de subsistência em ambientes de água doce na América do Sul. Essa família compreende 21 espécies e três gêneros. No presente estudo foram analisados os cariótipos de Prochilodus mariae, Semaprochilodus kneri e S. laticeps provenientes de Caicara del Orinoco, Estado Bolivar, Venezuela. As espécies P. mariae, S. kneri e S. laticeps apresentaram 2n=54 cromossomos (40 metacêntricos e 14 submetacêntricos), um único par de cromossomos com regiões organizadoras de nucléolo e uma grande quantidade de heterocromatina em posição centromérica e pericentromérica de quase todos os cromossomos. Os espécimes estudados de P. mariae apresentaram de 0 a 3 microcromossomos supranumerários. Os dados obtidos aqui confirmam a natureza conservada do número e da morfologia cromossômica dos Prochilodontidae e reforçam a hipótese de que pequenos rearranjos estruturais foram os principais eventos fixados na diversificação cariotípica do grupo.

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Section: Fig 1 Karyotypes Of: A) Prochilodus Mariae With 2n=54 Chrosupporting

confidence: 53%

Section: Fig 1 Karyotypes Of: A) Prochilodus Mariae With 2n=54 Chromentioning

confidence: 99%

Karyotypic characterization of Prochilodus mariae, Semaprochilodus kneri and S. laticeps(Teleostei: Prochilodontidae) from Caicara del Orinoco, Venezuela

et al. 2003

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“…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.…”

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confidence: 99%

“…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).…”

mentioning

confidence: 99%

“…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).…”

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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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