Physical mapping of plant DNA sequences by simultaneous in situ hybridization of two differently labelled fluorescent probes

Abstract

Two haptens, biotin and digoxigenin, were used to label two highly repetitive plant DNA sequences: pTa71 (a clone containing a ribosomal DNA sequence from wheat, Triticum aestivum) and pSc119.2 (a clone containing a 120-bp tandem repeat sequence from rye, Secale cereale). These probes were simultaneously localized by in situ hybridization on chromosome spreads of rye, Secale cereale cv. Petkus Spring. The ability to localize two sequences simultaneously will be of major importance for physically ordering DNA sequences along plant chromosomes.Key words: physical mapping, DNA–DNA in situ hybridization, Secale, fluorescent mapping, multiple labelling.