Dominant marker vectors for selecting yeast mating products

We have developed plasmid vectors to enable selection of diploids from mating reactions between haploid strains that lack compatible recessive genetic markers. The plasmids bear one of five different dominant selectable markers, kanMX4, hphMX4, natMX4, patMX3 or ZEO, a yeast origin of replication, and the URA3 gene. Diploids can be selected from mating reactions between haploids transformed with plasmids expressing different dominant markers, by using a combination of drugs that select for both markers. Following non-selective growth, diploids that subsequently become cured of the plasmids can be directly selected on 5-FOA, for ura3 auxotrophs, or identified by replica-plating onto appropriate selective media.