Physical mapping of 5S and 45S rDNA loci in pufferfishes (Tetraodontiformes).
Chromosomal features, location and variation of the major and minor rDNA genes cluster were studied in three pufferfish species: Sphoeroides greeleyi and Sphoeroides testudineus (Tetraodontidae) and Cyclichthys spinosus (Diodontidae). The location of the major rDNA was revealed with an 18S probe in two loci for all species. The minor rDNA loci (5S rDNA) was found in one chromosome pair in tetraodontid fishes and four sites located on two distinct chromosomal pairs in C. spinosus. A syntenical organization was not observed among the ribosomal genes. Signal homogeneity for GC/AT-DNA specific fluorochromes was observed in diodontid fish except in the NORs regions, which were CMA3-positive. Giemsa karyotypes of tetraodontid species presents 2n=46, having the same diploid value of other Sphoeroides species that have been investigated. On the other hand, the karyotype of C. spinosus, described for the first time, shows 2n=50 chromosomes (4m+18sm+12st+16a). The foreknowledge of the karyotypic structure of this group and also the physical mapping of certain genes could be very helpful for further DNA sequence analysis.
Noleto
Rafael Bueno
RB
Departamento de Genética, Centro Politécnico, Universidade Federal do Paraná, Caixa Postal 19071, 81531-990, Curitiba, PR, Brazil. rafanoleto@yahoo.com.br
Vicari
Marcelo Ricardo
MR
Cipriano
Roger Raupp
RR
Artoni
Roberto Ferreira
RF
Cestari
Marta Margarete
MM
D000818:Animals; D004275:DNA, Ribosomal / Q000235:genetics*; D005260:Female; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D020161:Physical Chromosome Mapping; D012335:RNA, Ribosomal / Q000235:genetics; D012341:RNA, Ribosomal, 5S / Q000235:genetics; D013045:Species Specificity; D023721:Tetraodontiformes / Q000145:classification / Q000235:genetics*
D004275:DNA, Ribosomal; D012335:RNA, Ribosomal; D012341:RNA, Ribosomal, 5S; C088179:RNA, ribosomal, 45S