Cytological Characterization of Transformed Plants: Mapping of Low-Copy and Repetitive DNA Sequences by Fluorescent In Situ Hybridization (FISH)

Abstract

The physical localization of DNA sequences to plant chromosomes by in situ hybridization (ISH) is becoming increasingly important in many areas of plant molecular biology. ISH has provided new information on the position and order of genes and DNA sequences on chromosomes (e.g. Plate Id, f and g; Leitch and Heslop-Harrison 1992, 1993; Leitch et al. 1994; Bennett et al. 1995; Cox et al. 1993; Lehfer et al. 1993). This will assist chromosome walking studies aiming to isolate genes of interest, and has enabled comparisons to be made between genetic and physical maps (e.g. Gustafson et al. 1990; Pedersen et al. 1995 and Laurie et al. 1993). Such data are increasingly being used to link the DNA sequence with higher orders of genome structure, gene activities and genetic recombination (e.g. Leitch et al. 1992, 1993; Lapitan 1992; Moore et al. 1993) and to understand the mechanisms of chromosome evolution (Parokonny et al. 1992; Kenton et al. 1993; Leitch et al. 1996). Moreover, ISH has been used to confirm plant transformation and to identify the site(s) of DNA insertion (Plate lh; Kenton et al. 1995; Ambros et al. 1986; Mouras et al. 1987; Mouras and Negrutiu 1989).