δ Sequences mediate DNA rearrangements in Saccharomyces cerevisiae.

A solo δ sequence flanking the 5' end of the ADHII structural gene, ADR2, can promote a number of DNA rearrangements some of which were investigated in detail. In a selective system haploid mutants were screened in which a solo S sequence flanking ADR2 had been joined to a Ty element. Three different types of events can create such a structure: Reintegration of a Ty sequence at the δ-ADR2 site, inversion of ADR2 and flanking material, and transposition of ADR2 along with 3' flanking material. The involvement of reciprocal or non-reciprocal exchange mechanisms in creating such events are discussed.