Ribosomal RNA genes are interspersed throughout a heterochromatic chromosome arm in Atlantic salmon.
The ribosomal RNA genes (rDNA) have been mapped by fluorescent in situ hybridization (FISH) using four rDNA probes (rDNA/FISH) to Atlantic salmon chromosomes. Signals appeared over the whole heterochromatic chromosome arm displaying the secondary constriction and satellites. The size polymorphism of this sort arm, revealed by C-banding, was confirmed by rDNA/FISH, supporting large interindividual differences in the number of rDNA copies. Conventional techniques for the detection of nucleolar organizer regions are discussed, and their results are compared with those of rDNA/FISH.
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Departamento de Biología Funcional, Facultad de Medicina, Universidad de Oviedo, Spain.
Morán
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Garcia-Vázquez
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D000818:Animals; D002478:Cells, Cultured; D002871:Chromosome Banding; D002874:Chromosome Mapping; D004275:DNA, Ribosomal; D006570:Heterochromatin; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D012335:RNA, Ribosomal / Q000235:genetics*; D012474:Salmon / Q000235:genetics*
D004275:DNA, Ribosomal; D006570:Heterochromatin; D012335:RNA, Ribosomal