Cytogenetic analysis of B chromosomes in one population of the fish Moenkhausia sanctaefilomenae (Steindachner, 1907) (Teleostei, Characiformes)
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2012-01-01
Autores
Hashimoto, Diogo Teruo [UNESP]
Voltolin, Tatiana Aparecida [UNESP]
Paes, Ana Danyelle Noitel Valim de Arruda [UNESP]
Foresti, Fausto [UNESP]
Bortolozzi, Jehud [UNESP]
Porto-Foresti, Fábio [UNESP]
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The aim of this study was to characterize cytogenetically one population of the fish Moenkhausia sanctaefilomenae (Steindachner, 1907), with emphasis on the analysis of B chromosomes. The nucleolar activity in the B microchromosomes was characterized, and an analysis of mitotic instability of these microchromosomes was accomplished. The results showed a diploid chromosome number of 50 chromosomes. In all individuals, we observed the presence of B microchromosomes with intra- and inter-individual variability. The analysis of the nucleolus organizing regions (NORs) by silver nitrate staining demonstrated multiple NORs. We observed active sites of ribosomal DNA in the B microchromosomes, with a frequency of 20% in the analyzed cells, which shows gene activity in these chromosomal elements. The analysis of constitutive heterochromatin patterns showed that the B microchromosomes are heterochromatic or euchromatic, which demonstrates differentiation of DNA composition between these genomic elements. The calculation of the mitotic instability index implied that B chromosomes in this species might be in a final stage of instability. © Diogo Teruo Hashimoto et al.
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Fish cytogenetic, Mitotic instability, NOR expression, Supernumerary chromosomes
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Comparative Cytogenetics, v. 6, n. 2, p. 141-151, 2012.