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Chromosomal painting and ZW sex chromosomes differentiation in Characidium (Characiformes, Crenuchidae)
Tatiana C Machado, José C Pansonato-Alves, Marcela B Pucci, Viviane Nogaroto, Mara C Almeida, Claudio Oliveira, Fausto Foresti, Luiz AC Bertollo, Orlando Moreira-Filho, Roberto F Artoni, Marcelo R Vicari
BMC Genetics , 2011, DOI: 10.1186/1471-2156-12-65
Abstract: A W-specific probe for efficient chromosome painting was isolated by microdissection and degenerate oligonucleotide primed-polymerase chain reaction (DOP-PCR) amplification of W chromosomes from C. gomesi. The W probe generated weak signals dispersed on the proto sex chromosomes in C. zebra, dispersed signals in both W and Z chromosomes in C. lauroi and, in C. gomesi populations revealed a proximal site on the long arms of the Z chromosome and the entire W chromosome. All populations showed small terminal W probe sites in some autosomes. The 18S rDNA revealed distinctive patterns for each analyzed species/population with regard to proto sex chromosome, sex chromosome pair, and autosome location.The results from dual-color fluorescence in situ hybridization (dual-color FISH) using W and 18S rDNA probes allowed us to infer the putative evolutionary pathways for the differentiation of sex chromosomes and NORs, from structural rearrangements in a sex proto-chromosome, followed by gene erosion and heterochromatin amplification, morphological differentiation of the sex chromosomal pair, and NOR transposition, giving rise to the distinctive patterns observed among species/populations of Characidium. Biogeographic isolation and differentiation of sex chromosomes seem to have played a major role in the speciation process in this group of fish.The Crenuchidae is widespread in freshwater systems of the South and Central Americas [1]. The Characidium is the most representative group in this family, comprising 50 valid species [1]. This is a particularly interesting Neotropical fish group for cytogenetic studies because it presents a diversified model of sex chromosomes [2]. In the Characidium, a diploid number of 50 chromosomes is observed in all studied species and a karyotype of 32 m + 18 sm is most commonly reported [2-10].Although the diploid number is conserved, the Characidium exhibit remarkable interspecific and interpopulation differences, such as (i) inter- and intrain
Cytogenetic divergence between two sympatric species of Characidium (Teleostei, Characiformes, Crenuchidae) from the Machado River, Minas Gerais, Brazil
Silva, Alexandre Rodrigues da;Maistro, Edson Luis;
Genetics and Molecular Biology , 2006, DOI: 10.1590/S1415-47572006000300010
Abstract: cytogenetic studies were performed on two sympatric species of characidium, c. gomesi and c. cf. zebra, from the grande river basin, minas gerais state, brazil. although both species had a chromosome number of 50 with a karyotype exclusively consisting of meta- and submetacentric chromosomes, interspecific diversity was detected concerning the size of the two first chromosome pairs of the karyotypes. active nucleolus organizer regions (nors) were located at the terminal position on the long arm of the 17th pair of c. gomesi and at subterminal position on the long arm of the 23rd pair of c. cf. zebra. for both species the fluorochrome cma3 stained only the nor-bearing pair of chromosomes. the heterochromatin pattern also showed some differentiation between these species restricted to the centromeric or pericentromeric region of c. cf. zebra and practically absent in c. gomesi. these data are discussed concerning chromosome diversification in this fish group.
Characidium heirmostigmata, a new characidiin fish (Characiformes: Crenuchidae) from the upper rio Paraná basin, Brazil
Gra?a, Weferson J. da;Pavanelli, Carla S.;
Neotropical Ichthyology , 2008, DOI: 10.1590/S1679-62252008000100006
Abstract: characidium heirmostigmata new species is described from the rio ivaí drainage, upper rio paraná basin, paraná state, brazil. the new species is diagnosed among its congeners by the possession of eight to 11 incomplete oblique dark bars on the body sides, extending upwards and downwards from the lateral line, independently of the eight or nine dorsal transverse bars usually present in species of characidium. the new species is similar to characidium serrano from the upper rio uruguay basin, but differs by meristic and morphometric traits.
Characidium xanthopterum (Ostariophysi: Characiformes: Crenuchidae): a new species from the Central Brazilian Plateau
Silveira, Luiz G. G.;Langeani, Francisco;Gra?a, Weferson J. da;Pavanelli, Carla S.;Buckup, Paulo A.;
Neotropical Ichthyology , 2008, DOI: 10.1590/S1679-62252008000200003
Abstract: characidium xanthopterum is described from tributaries of the upper rio paraná and upper rio tocantins basins, in the central brazilian plateau, goiás state, brazil. the new species is diagnosed among congeners by the absence of dark bars on the sides of the body in adult specimens, and by the deep yellow coloration in all fins. ontogenetic change of color pattern is recorded for the first time for characidium species. specimens smaller than 32 mm sl possess dark bars on body. these bars disappear with growth between 32 and 35 mm sl, and are always absent in individuals larger than 35 mm sl.
Karyotypic conservatism in samples of Characidium cf. zebra (Teleostei, Characiformes, Crenuchidae): physical mapping of ribosomal genes and natural triploidy
Pansonato-Alves, José Carlos;Oliveira, Claudio;Foresti, Fausto;
Genetics and Molecular Biology , 2011, DOI: 10.1590/S1415-47572011005000005
Abstract: basic and molecular cytogenetic analyses were performed in specimens of characidium cf. zebra from five collection sites located throughout the tietê, paranapanema and paraguay river basins. the diploid number in specimens from all samples was 2n = 50 with a karyotype composed of 32 metacentric and 18 submetacentric chromosomes in both males and females. constitutive heterochromatin was present at the centromeric regions of all chromosomes and pair 23, had additional interstitial heterochromatic blocks on its long arms. the nucleolar organizer regions (nors) were located on the long arms of pair 23, while the 5s rdna sites were detected in different chromosomes among the studied samples. one specimen from the alambari river was a natural triploid and had two extra chromosomes, resulting in 2n = 77. the remarkable karyotypic similarity among the specimens of c. cf. zebra suggests a close evolutionary relationship. on the other hand, the distinct patterns of 5s rdna distribution may be the result of gene flow constraints during their evolutionary history.
Aspectos da reprodu o no gênero Characidium Reinhardt, 1867 (Crenuchidae, Characidiinae), na microbacia do Ribeir o Grande, serra da Mantiqueira, sudeste do Brasil = Reproduction aspects of the genus Characidium Reinhardt, 1867 (Crenuchidae, Characidiinae) in the Ribeir o Grande system, serra da Mantiqueira, southeastern Brazil
Francisco Manoel de Souza Braga
Acta Scientiarum : Biological Sciences , 2006,
Abstract: Neste trabalho s o descritos aspectos da biologia da reprodu o em Characidium lauroi e C. alipioi. A matura o das g nadas é dividida em quatro estádios e s o descritos no ciclo anual. Em Characidium lauroi, existe um maior período reprodutivo na primavera e, em C. alipioi o maior período reprodutivo é no ver o. O tamanho da primeira matura o gonadal foi ao redor de 4,2 cm de comprimento total para machos e de 5,1 cm para fêmeas de Characidium lauroi, para machos de C. alipioi, foi ao redor de 6,2 cm de comprimento total e, para fêmeas, foi de 5,8 cm. Os valores da rela o gonadossomática indicam o estádio de maturidade e foram determinados para cada espécie e sexo. Os altos valores vistos em outubro para machos e fêmeas de Characidium lauroi marcam os picos de matura o em ambos os sexos, e os picos coincidem com o período reprodutivo. Para Characidium alipioi, os picos foram em fevereiro e também coincidem com o período reprodutivo. Aspects of the reproductive biology of Characidium lauroi and C. alipioi were described. Maturation of the gonads was divided into four stages, and the distribution of the stages in an annual cycle was reported. The Characidium lauroi has a higher spawning period in the spring, and the C. alipioi, in the summer. The size at sexualmaturity of the Characidium lauroi was about 4.2 cm total length for males and 5.1 cm for females; as for the C. alipioi, males were about 6.2 cm total length and females were about 5.8 cm. The gonadosomatic index values indicated the stage of maturity and were determined for each species and sex. The high values observed in October for Characidium lauroi males and females mark the maturation peaks in both sexes, and the peaks coincided with the spawning period. As for C. alipioi, the peaks were in February and also coincided with the spawning period.
Life-history of the South American darter, Characidium pterostictum (Crenuchidae): evidence for small scale spatial variation in a piedmont stream
Becker, Fernando Gertum;Carvalho, Silene de;Hartz, Sandra Maria;
Neotropical Ichthyology , 2008, DOI: 10.1590/S1679-62252008000400007
Abstract: the present study compares the reproduction, condition and size of the small characiform fish, characidium pterostictum, sampled at close sites differing in severity of flash flood effects. data were obtained from seasonal samples in two sites situated 8 km apart in the same stream. in the upstream site, habitat is more severely affected by flash floods than in the downstream site, and this difference was hypothesized to produce differences in life history and individual reproduction trade-off patterns, as predicted by life-history theory. the results provided evidence for small-scale spatial variation in life-history and trade-off patterns within the studied population. at the most severely disturbed site, c. pterostictum displayed a trade-off pattern that favored reproductive life-span (e.g., larger size, higher and seasonally stable condition, larger mean size of mature females) over instantaneous reproductive output (lower gonadosomatic index), while the opposite pattern was observed in the less disturbed site. because of the differences in disturbance effects between each sampling site, these results suggest that within-stream variability in the severity of hydrological disturbance can influence life-history patterns at small spatial scales. an implication of the results is that fish occupying areas that are hydrologically more variable within a stream are not necessarily at an energetic or reproductive disadvantage, but may be simply under environmental conditions that favor distinct patterns of energy allocation (or trade-offs) and population persistence, as predicted by life-history theory. therefore, plasticity in life-history is expected to be common in stream fish populations that are widespread in a stream system with spatially variable or patchy habitat characteristics.
Advances in interspecific pregnancy
Xichao Wang,Bojie Dai,Enkui Duan,Dayuan Chen
Chinese Science Bulletin , 2001, DOI: 10.1007/BF02900547
Abstract: Interspecific pregnancy in which the conceptus and female carrying the pregnancy are of different species is a key step to interspecific cloning. Cloning endangered animals by interspecific pregnancy is such a highlight catching people’s eyes nowadays. In this article, the history of interspecific pregnancy, the methods for establishment of interspecific pregnancy, the corresponding theories, barriers and applied prospects are reviewed.
Dinamica populacional de Characidium lauroi e C. alipioi (Teleostei, Crenuchidae) na microbacia do Ribeir o Grande, serra da Mantiqueira Oriental, Estado de S o Paulo = Population dynamics of Characidium lauroi and C. alipioi (Teleostei, Crenuchidae) in the Ribeir o Grande microbasin, eastern Serra da Mantiqueira, S o Paulo State  [cached]
Francisco Manoel de Souza Braga,Ursulla Pereira Souza,Alberto Luciano Carmassi
Acta Scientiarum : Biological Sciences , 2007,
Abstract: Em riachos de pequena ordem, o alto e variável fluxo de água oferece tanto vantagens como desvantagens para o ciclo de vida de peixes. Mesmo espécies próximas que vivem em habitats semelhantes podem apresentar diferen as em seus padr es de ciclo de vida. Com base na distribui o de tamanho de ovócitos, C. lauroi foi classificada no tipo de desova parcelada, e C. alipioi no tipo de desova total. A fecundidade absoluta de C. lauroi variou de 1.313 a 2.925 ovócitos; em C. alipioi, a fecundidade absoluta variou de 2.213 a 25.550 ovócitos. A prova n o-paramétrica de correla o de Spearman mostrou haver significancia entre a rela o gonadossomática e a fecundidade para ambas as espécies. Os parametros de crescimento, a taxa de mortalidade natural e a taxa de sobrevivência para fêmeas de C. lauroi foram: K = 0,68 ano-1, Loo = 8,7 cm, tmax = 4,4 anos, M = 1,62 ano-1, S = 19,79%, e para machos: K = 0,78 ano-1, Loo = 6,9 cm, tmax = 3,8 anos, M = 1,89 ano-1, S = 15,11%. Os parametros de crescimento, a taxa de mortalidade natural e a taxa de sobrevivência para fêmeas de C. alipioi foram: K = 0,90 ano-1, Loo = 12,2 cm, tmax = 3,3 anos,M = 1,81 ano-1, S = 16,37%, e para machos: K = 0,76 ano-1, Loo = 10,1 cm, tmax = 3,9 anos, M = 1,71 ano-1, S = 18,10%. In low-order streams, the high and variable water flow rates offer both advantages and disadvantages to the life cycle of fishes. Even closely related species living in similar habitats can show differences in life history patterns. Based on oocyte-sizedistributions, C. lauroi was classified into the fractional spawning type, and C. alipioi into the total spawning type. The absolute fecundity of C. lauroi ranged from 1,313 to 2,925 oocytes; in C. alipioi the absolute fecundity ranged from 2,213 to 25,550 oocytes. The nonparametric Spearman correlation test showed statistical significance between the gonadosomatic index and fecundity for both species. The growth parameters, natural mortality rate and survivalrate for females of C. lauroi were: K = 0.68 yr-1, Loo = 8.7 cm, tmax = 4.4 years, M = 1.62 yr-1, S = 19.79%, and for males: K = 0.78 yr-1, Loo = 6.9 cm, tmax = 3.8 years, M = 1.89 yr-1, S = 15.11%. The growth parameters, natural mortality rate and survival rate for females ofC. alipioi were: K = 0.90 yr-1, Loo= 12.2 cm, tmax = 3.3 years, M = 1.81 yr-1, S = 16.37%, and for males: K = 0.76 yr-1, Loo = 10.1 cm, tmax = 3.9 years, M = 1.71 yr-1, S = 18.10%.
Cytogenetic divergence in two sympatric fish species of the genus Astyanax Baird and Girard, 1854 (Characiformes, Characidae) from northeastern Brazil
Medrado, Aline Souza;Ribeiro, Mavione Souza;Affonso, Paulo Roberto Antunes de Mello;Carneiro, Paulo Luíz Souza;Costa, Marco Ant?nio;
Genetics and Molecular Biology , 2012, DOI: 10.1590/S1415-47572012005000075
Abstract: the fish genus astyanax is widespread throughout the neotropical region and is one of the most species-rich genera of the characiformes. cytogenetic studies of astyanax have revealed marked intra-and interspecific diversity, with the identification of various species complexes. in this report, we describe the karyotypic structure of two sympatric species of astyanax (astyanax sp. and astyanax aff. fasciatus) from the middle contas river basin in the northeastern brazilian state of bahia. both species had 2n = 48 but differed in their karyotypic formulae. small heterochromatic blocks and multiple nucleolar organizer regions (nors) were identified in both species. terminal cma3+/dapi-signals were observed in astyanax sp. and a. aff. fasciatus, mostly coincident with nors. these results show that chromosomal markers can be used to identify species in this fish complex. these markers can provide useful information for evolutionary studies and investigations on the mechanisms of chromosomal diversity in astyanax.
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