Duplication processes in Saccharomyces cerevisiae haploid strains

Duplication is thought to be one of the main pro-cesses providing a substrate on which the effects of evolution are visible. The mechanisms underly-ing this chromosomal rearrangement were inves-tigated here in the yeast Saccharomyces cerevisiae. Spontaneous revertants containing a duplication event were selected and analyzed. In addition to the single gene duplication described in a previous study, we demonstrated here that direct tandem duplicated regions ranging from 5 to 90 kb in size can also occur spontaneously. To further investigate the mechanisms in the duplication events, we exam-ined whether homologous recombination contributes to these processes. The results obtained show that the mechanisms involved in segmental duplication are RAD52-independent, contrary to those involved in single gene duplication. Moreover, this study shows that the duplication of a given gene can occur in S.cerevisiae haploid strains via at least two ways: single gene or segmental duplication