DETECTION OF A 2.6-KB SINGLE LOW COPY DNA-SEQUENCE ON CHROMOSOMES OF WHEAT (TRITICUM-AESTIVUM) AND RYE (SECALE-CEREALE) BY FLUORESCENCE IN-SITU HYBRIDIZATION

A fluorescence in situ hybridization procedure was developed to detect a 2.6 kb single/low copy DNA sequence on chromosomes of wheat (Triticum aestivum) and rye (Secale cereale). The probe, pTtksuI26, was from the wheat genomic library generated at Kansas State University and was labeled with Bio-11-dUTP by nick translation. The signal was amplified by a protocol of avidin-FITC (fluorescein isothiocyanate), biotinylated goat anti-avidin antibody, avidin-FITC. Two rye chromosomes and several wheat chromosomes showed the hybridization sites. The multiple sites in wheat are probably the result of the homoeologous nature of the three genomes in wheat. The ability to detect the hybridization signal of a small single/low copy DNA sequence is a very important step towards the physical mapping of plant genomes. This procedure might also be useful for studying the genomic relationship among wheat relative species.