Cytogenetics of the redtail catfish

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Swarça, A. C., Dias, A. L., & Fenocchio, A. S. 2017. Cytogenetic studies in the redtail catfish, Phractocephalus hemioliopterus (Bloch & Schneider, 1801)(Siluriformes, Pimelodidae) a giant fish from Amazon basin. Comparative Cytogenetics, 11(1), 119–128. doi:10.3897/CompCytogen.v11i1.11152

https://compcytogen.pensoft.net/articles.php?id=11152

ABSTRACT

The objective of this study was to cytogenetically analyze

Phractocephalus hemioliopterus

comparing the findings with other data to infer relationships among Pimelodidae species. The results revealed a diploid number of 2n = 56 and the karyotype composed of 16 metacentric, 20 submetacentric, 6 subtelocentric and 14 acrocentric chromosomes (FN = 98). The Ag-NORs, 18S rDNA and CMA3 signals were coincident in location occupying the short arm of an acrocentric chromosome pair (23th), in a secondary constriction. The 5S rDNA genes were localized near the centromere on the short arms of one submetacentric chromosome pair. C-bands were localized predominantly in the terminal regions of chromosomes, including the AgNORs and a small metacentric pair with a conspicuous positive band on interstitial region. This chromosome pair could be considered a species-specific cytogenetic marker.

• Keywords: Neotropical fish, Parrot catfish, karyotype, Ag-NORs, 18S rDNA, CMA3, C-banding