title: Cytogenetic analysis of platyfish (Xiphophorus maculatus) shows location of major and minor rDNA on chromosomes.
abstract: Chromosome distribution of nucleolus organizer regions (NORs) and 5S rDNA loci were investigated in platyfish (Xiphophorus maculates) using conventional and molecular cytogenetic techniques. Chromomycin A3 (CMA3) staining of GC- rich heterochromatin provided four CMA3 cytotypes in studied platyfish. As in fish, CMA3 positive sites are related to NORs, chromosomes sequentially stained by CMA3 and AgNO3 showed bright blocks that were transcriptionaly active NORs. Additionally, PRINS with primers enabling amplification of 5S rDNA and CMA3 staining revealed existence of 5S rDNA sites located close to GC rich regions. The analysis could suggests that minor and major rDNAs may be linked.
authors.affiliation: Department of Evolutionary Genetics, University of Warmia and Mazury in Olsztyn, Poland. con@uwm.edu.pl
authors.forename: Konrad
authors.initials: K
authors.lastname: Ocalewicz
mesh_terms: D000818:Animals; D014128:Chromomycin A3; D002874:Chromosome Mapping; D003532:Cyprinodontiformes / Q000235:genetics*; D020732:Cytogenetic Analysis; D005260:Female; D005456:Fluorescent Dyes; D008297:Male; D009697:Nucleolus Organizer Region; D012341:RNA, Ribosomal, 5S / Q000235:genetics*; D016622:Silver Staining
chemical_list: D005456:Fluorescent Dyes; D012341:RNA, Ribosomal, 5S; D014128:Chromomycin A3