Mild overexpression of NDC1 causes haploid cells to increase in ploidy. Haploid yeast strains (WX257–2d, WX257–4c, HC14–10c, and HC14–5d; see Table 1) were transformed with either a 2-μm URA3 vector (2-μm vector; pRS426) or with the 2-μm URA3 vector containing NDC1 (2-μm NDC1; pRS426-NDC1). After transformation, individual colonies (n = 33 for vector alone; n = 112 for 2-μm NDC1) were selected and inoculated into Ura− broth overnight, and samples were prepared for flow cytometry the following day. Shown here are examples of flow cytometric profiles for haploid strains transformed with either the 2-μm vector or with the 2-μm vector containing NDC1.