Physical mapping of 5S rDNA reveals a new locus on 3R and unexpected complexity in a rye translocation used in chromosome mapping

Abstract

Using fluorescence in situ hybridization (FISH) with probe pScT7, three different 5S rDNA loci were detected in the satellite of rye chromosome 1R (5SDna-R1) and in the short arms of chromosomes 3R (5SDna-R3) and 5R (5SDna-R2) respectively. All three loci showed polymorphism for the hybridization signal intensity. In order to determine the localization of these rye 5S rDNA multigene loci with higher precision within the corresponding chromosome arms, the probe pScT7 was physically mapped by FISH in relation to the following five translocations (Wageningen Tester Set): T850W (1RS/4RL), T248W (1RS/6RS), T273W (1RS/5RL), T305W (2RS/5RS) and T240W (3RS/5RL). Accurate physical maps of the translocation breakpoints had previously been made using electron microscope analysis of spread pachytene synaptonemal complexes of heterozygotes for the different translocations. The results indicate that locus 5SDna-R3 is located between the breakpoint of translocation T240W and the telomere, whereas locus 5SDna-R2 is located between the breakpoint of translocation T305W and the centromere, the hybridization of probe pScT7 on T305W translocated chromosomes demonstrating the complex nature of this translocation. On the other hand, the simultaneous detection of probes pScT7 and pTA71 (18S-5.8S-26S rDNA) with two different fluorochromes, indicated that the breakpoints of translocations T850W and T248W are located between loci Nor-R1 and 5SDna-R1.

New ribosomal RNA gene locations in Gossypium hirsutum mapped by meiotic FISH

“…In several cases, improved in situ hybridization (ISH) techniques have led to identification of new rDNA loci (Alonso-Blanco et al 1994;Cuadrado et al 1995;Fominaya et al 1995). Until recently, this was best exemplified in wheat.…”

Rapid isolation of recombinant lambda phage DNA for use in fluorescence in situ hybridization

“…Using conventional in situ hybridization techniques, three loci for the 5S RNA genes of rye were physically mapped on the satellite of chromosome 1R (5S-Rrna-R1), in the middle of the short arm of chromosome 5R (5S-Rrna-R2) and in the distal half of chromosome arm 3RS (5S-Rrna-R3) (Appels et al 1980, Reddy & Appels 1989, Alonso-Blanco et al 1994, Cuadrado et al 1995. The 5S rRNA repeating units in rye consist of two clear lineages corresponding to the short (1R) and the long units (5R) (Reddy & Appels 1989).…”

Fluorescence in situ hybridization of single copy transgenes in rice chromosomes

“…It has been used for physical mapping (Zwick et al, 1998;Ji et al, 1999), determination of the chromosomal status of genes in regard to their presence (Taga and Murata, 1994;Brandes et al, 1995;Busch et al, 1995;Rusche et al, 1997;Gill and Friebe, 1998;Presting et al, 1998;Zhang et al, 1998;Brown et al, 1999) and translocation (Alonso-Blanco et al, 1994;Cuadrado and Jouve, 1995;Wang and Zhang, 1996). Genetic relationships among related species have also been addressed using FISH (de Bustos et al, 1996).…”