Expansion and contraction of the DUP240 multigene family in Saccharomyces cerevisiae populations

Abstract

The influence of duplicated sequences on chromosomal stability is poorly understood. To characterize chromosomal rearrangements involving duplicated sequences, we compared the organization of tandem repeats of the DUP240 gene family in 15 Saccharomyces cerevisiae strains of various origins. The DUP240 gene family consists of 10 members of unknown function in the reference strain S288C. Five DUP240 paralogs on chromosome I and two on chromosome VII are arranged as tandem repeats that are highly polymorphic in copy number and sequence. We characterized DNA sequences that are likely involved in homologous or nonhomologous recombination events and are responsible for intra- and interchromosomal rearrangements that cause the creation and disappearance of DUP240 paralogs. The tandemly repeated DUP240 genes seem to be privileged sites of gene birth and death.