Karyotype and nucleolar organizer regions of pygocentrus cariba (serrasalminae) from Caicara del Orinoco, Venezuela
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2005
- handle: 10670/1.s7qmi6
- 0378-1844
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Ángel Granado et al., « Karyotype and nucleolar organizer regions of pygocentrus cariba (serrasalminae) from Caicara del Orinoco, Venezuela », Interciencia, ID : 10670/1.s7qmi6
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"Cytogenetic studies were conducted on Pygocentrus caribafrom Caicara del Orinoco, Venezuela. The diploid chromosomenumber 2n=60 consisted of 18 metacentric, 30 submetacentric, 2subtelocentric and 10 acrocentric chromosomes (NF= 110). Amaximum of 12 nucleolar organizer regions (NOR) bearing chromosomeswere visualized, with the NORs located terminally onthe short arms of one pair of medium sized metacentric chromosomes,and on five small-sized acrocentric chromosome pairs.Constitutive heterochromatin blocks were located at centromericand telomeric regions of practically all chromosomes, some beingmore conspicuous than others. Similarities between P. caribaand the species of the genus Serrasalmus so far studied, in termsof the number and type of chromosomes, multiplicity of NORbearingchromosomes and the distribution of constitutive heterochromatinlocated in centromeric and telomeric position, reinforcesthe hypothesis of the close phylogenetic relationship betweenthe genera Pygocentrus and Serrasalmus."