Critical points of fish for the localization of single and low copy sequences in plant chromosomes

Fluorescence In Situ Hybridization (FISH) is a powerful means by which single and low copy DNA sequences can be localized on chromosomes. Although great progress has been made in the last few years and some reports already exist for the detection of single and low copy sequences of only a few kilobase pairs in length, the detection of these sequences is still difficult in plants. An overview is presented here on the important and unclear points in FISH for the localization of single and low copy sequences in plants.