MAPPING OF REPEATED DNA-SEQUENCES IN PLANT CHROMOSOMES BY PRINS AND C-PRINS

The primed in situ DNA labelling (PRINS) procedure was optimised for t he rapid physical mapping of several types of repetitive DNA sequences on the mitotic chromosomes of Vicia faba, Pisum sativum and Secale ce reale. A localization of the highly repeated FokI sequence on V. faba chromosomes was achieved after a 7-min total reaction time. In additio n, we report a procedure for direct cycling-PRINS (C-PRINS), a variati on of PRINS which involves a sequence of thermal cycles analogous to t he polymerase chain reaction. Compared to PRINS, C-PRINS was more sens itive. Further work is needed to improve the sensitivity of the reacti on to allow for the reliable detection of low-copy DNA sequences.