Oliveira, Claudio [UNESP]Gosztonyi, Atila E.2014-05-272014-05-272000-01-01Caryologia, v. 53, n. 1, p. 31-37, 2000.0008-7114http://hdl.handle.net/11449/66051The mitotic chromosomes, nucleolus organizer regions (NORs), C-banding pattern and nuclear DNA content of Diplomystes mesembrinus were studied. The karyotype, with 2n=56 chromosomes (22m+24sm+6st+4a), has a high chromosome arm number (NF = 102), one chromosome pair with NORs, and a very small amount of heterochromatin. The NOR-bearing arm is entirely heterochromatic and exhibits a marked size polymorphism. The diploid DNA content detected in erythrocyte nuclei of D. mesembrinus was 2.57 ± 0.15 pg/nucleus. The chromosome evolution in Siluriformes is discussed on the basis of available cytogenetic data and it is proposed that 2n=56 is synapomorphic for the order.31-37engC-bandCytogeneticsDiplomystes mesembrinusDiplomystidaeDNA contentNORSiluriformesArtigo10.1080/00087114.2000.10589178WOS:000089280000004Acesso restrito2-s2.0-0013102899