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Registros recuperados: 3
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B chromosome and NORs polymorphism in Callichthys callichthys (Linnaeus, 1758) (Siluriformes: Callichthyidae) from upper Paraná River, Brazil Neotropical Ichthyology
Konerat,Jocicléia Thums; Bueno,Vanessa; Baumgartner,Lucas; Martins-Santos,Isabel Cristina; Margarido,Vladimir Pavan.
B chromosomes are extra chromosomes from the normal chromosomal set, found in different organisms, highlighting their presence on the group of fishes. Callichthys callichthys from the upper Paraná River has a diploid number of 56 chromosomes (26 m-sm + 30 st-a) for both sexes, with the presence of a sporadically acrocentric B chromosome. Moreover, one individual presented a diploid number of 57 chromosomes, with the presence of a morphologically ill-defined acrocentric B chromosome in all analyzed cells. The physical mapping of 5S and 18S rDNA shows multiple 5S rDNA sites and only one pair of chromosomes with 18S sites in C. callichthys, except for two individuals. These two individuals presented a third chromosome bearing NORs (Ag-staining and 18S rDNA)...
Tipo: Info:eu-repo/semantics/article Palavras-chave: 18S rDNA; 5S rDNA; Chromosomal rearrangements; FISH; Supernumerary chromosome.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252014000300603
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B chromosomes in a population of Astyanax eigenmanniorum (Characiformes, Characidae) from the Araguari River Basin (Uberlândia, MG, Brazil) Genet. Mol. Biol.
Torres-Mariano,Alessandra Ribeiro; Morelli,Sandra.
A cytogenetic study was conducted on an Astyanax eigenmanniorum population from the Caetano Stream (18° 44' 56" S/ 048° 18' 39" W) - in Uberlândia, MG, Brazil - showing a modal diploid number of 48 chromosomes in the standard male and female karyotypes. However, in several specimens it was also possible to observe metaphases with one or two B chromosomes, increasing the diploid number to 49 or 50 chromosomes, respectively. The supernumerary chromosomes were totally heterochromatic and highlighted after C-banding. The silver-stained nucleolus organizing regions (Ag-NORs) were located in at least five chromosomes of the standard karyotype, thus characterizing a multiple NOR system in the species. This is the first occurrence of an A. eigenmanniorum...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Characidae; Astyanax eigenmanniorum; Supernumerary chromosome; Heterochromatin; Nucleolus organizing regions (NORs).
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000200015
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Intraspecific crosses resulting in the first occurrence of eight and nine B chromosomes in Prochilodus lineatus (Characiformes, Prochilodontidae) Genet. Mol. Biol.
Voltolin,Tatiana Aparecida; Senhorini,José Augusto; Foresti,Fausto; Bortolozzi,Jehud; Porto-Foresti,Fábio.
B chromosomes are supernumerary elements present in about 15% of eukaryotic species and are most frequently heterochromatic, behave parasitically, show a transmission rate higher than standard (A) chromosomes, and can provoke harmful effects on carriers. In the current work, Prochilodus lineatus individuals carrying eight and nine B chromosomes were obtained by induced crossing performed involving breeders with different B chromosome numbers in their cells. The high B chromosome numbers found in the offspring were recorded for the first time in this species. The use of cytogenetic techniques applied in the present study revealed that regardless of the increase in number of B chromosomes in the genome of these individuals, those elements did not presented...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Supernumerary chromosome; Heterochromatic chromosome; Cross-fertilization.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572011000200009
Registros recuperados: 3
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