A SEARCH FOR AN ESSENTIAL FUNCTION OF THE REPLICATION ORIGIN ARS1 IN THE LIFE-CYCLE OF SACCHAROMYCES-CEREVISIAE

We have investigated the significance of the chromosomal replication o rigin, ARSI, during the entire life cycle of yeast. This was done by s ubstituting the chromosomal copy with a series of arsl deletion mutant s. It was shown that the ARSI replication origin is not essential for mitotic or premeiotic DNA replication since no effect on growth, chrom osomal loss rate and spore viability was observed in the arsl mutant s trains. We conclude that replication origins are abundantly, present i n the yeast genome and that the removal of a single replication origin is compensated for by replication forks emanating from neighbouring o rigins.