Possible origins of B chromosomes in Rineloricaria pentamaculata (Loricariidae, Siluriformes) from the Paraná River basin

We made a cytogenetic study of Rineloricaria pentamaculata from the Tauá Stream, in the Pirapó River sub-basin in Paraná State, Brazil, focused on the occurrence and origins of the B chromosomes. The diploid number varied from 2n = 56 to 2n = 59, due to the presence of 0 to 3 B microchromosomes of t...

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Bibliographic Details
Published in:Genetics and molecular research 2010-01, Vol.9 (3), p.1654-1659
Main Authors: Porto, F E, Portela-Castro, A L B, Martins-Santos, I C
Format: Article
Language:English
Subjects:
Animals
Catfishes - genetics
Chromosomes - genetics
Freshwater
Heterochromatin - genetics
Loricariidae
Rineloricaria pentamaculata
Siluriformes
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Summary:We made a cytogenetic study of Rineloricaria pentamaculata from the Tauá Stream, in the Pirapó River sub-basin in Paraná State, Brazil, focused on the occurrence and origins of the B chromosomes. The diploid number varied from 2n = 56 to 2n = 59, due to the presence of 0 to 3 B microchromosomes of the acrocentric type, which were observed in 92.3% of the specimens (N = 12). These chromosomes were totally heterochromatic, with the C banding technique, and there were inter- and intraindividual numerical differences. Meiotic cells in metaphase I had 28 bivalent chromosomes and 0 to 3 univalent chromosomes. We suggest that the B microchromosomes are centric fragments originated from chromosome rearrangements.
ISSN:1676-5680
1676-5680
DOI:10.4238/vol9-3gmr859