Fig. 3. High-fidelity DNA ligation is required in the absence of both MSH2 and RAD27.

a A diploid yeast strain heterozygous for cdc9-EE/AA, msh2Δ, and rad27Δ was sporulated, dissected, and the haploid spore colonies were genotyped by appropriate marker selection. 1–7 are tetrad dissections and A–D are haploid spore colonies. Plates were imaged after 3 days growth on YPDA at 30 °C. b Microscopic images of the indicated microcolonies taken after 5 days of growth reveals that the cdc9-EE/AA msh2Δ rad27Δ haploid derivatives sporulated but only divided a finite number of times. Thirteen dissections were performed using three independently derived diploid strains and similar results were obtained each time.