Is there replication-associated mutational pressure in the Saccharomyces cerevisiae genome?

Compositional bias of yeast chromosomes was analysed using detrended DNA walks. Unlike eubacterial chromosomes, the yeast chromosomes did not show the specific asymmetry correlated with origin and terminus of replication. It is probably a result of a relative excess of autonomously replicating sequences (ARS) and of random choice of these sequences in each replication cycle. Nevertheless, the last ARS from both ends of chromosomes are responsible for unidirectional replication of subtelomeric sequences with pre-established leading/lagging roles of DNA strands. In these sequences a specific asymmetry is observed, resembling the asymmetry introduced by replication-associated mutational pressure into eubacterial chromosomes. Copyright 2000 Academic Press.