Mapping of ribosomal genes and chromosomal markers in three species of the genusSerrasalmus(Characidae, Serrasalminae) from the Amazon basin

Genetics and Molecular Biology

Celeste M. Nakayama¹  Eliana Feldberg¹  Luiz Antonio C. Bertollo¹ 

关键词: chromosome banding;    cytotaxonomy of piranhas;    FISH;    karyotype;    ribosomal DNA;   

DOI  :  10.1590/S1415-47572008005000018

来源: SciELO

【 摘 要 】

Karyotypic characteristics of three species of the genusserrasalmus( S. altispinnis ,S. gouldingiandS. Serrulatus ) from the middle and lower Negro River, Amazon Basin, were investigated using different staining techniques and Fluorescentin situhybridization with 5S and 18S rDNA probes. The diploid number was invariably 2n = 60 and the fundamental number was FN = 110. Nevertheless, the karyotypes differed from each other in composition: 24m, 20sm, 6st, 10a inS. altispinnis ; 22m, 22sm, 6st, 10a inS. gouldingiand 20m, 22sm, 8st, 10a inS. serrulatus.The karyotype ofS. altispinnisdiffered from the one previously described in a population from the Pitinga River. C-positive constitutive heterochromatin was mainly pericentromeric in the karyotypes of all species. Nucleolar organizer regions were multiple and preferentially located terminally on the short arms of the subtelocentric/acrocentric chromosomes, as evidenced by both silver nitrate staining and fluorescentin situhybridization with the 18S rDNA probe. The maximum number of NORs varied among species, as did the NOR-bearing chromosomes. FISH with the 5S rDNA probe produced an interstitial signal on the long arms of the pair 7 in all species, coincident with a C-positive heterochromatic band. While some chromosome features were shared by the three species, some were species-specific and thus useful for cytotaxonomy.

【 授权许可】

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