TABLE 3.

Relative plating efficiencies of ten1-ts strains at 23° (percentage)

Strain genotype	TRP1 Plasmid
	TEN1	ten1-101	ten1-103	ten1-105	ten1-106
RAD52 ten1Δ	47 ± 24	2.1 ± 0.8	1.0 ± 0.6	1.2 ± 1.0	0.6 ± 0.6
rad52Δ ten1Δ	40 ± 15	0.5 ± 0.5	0.2 ± 0.3	0.2 ± 0.1	0.4 ± 0.6
exo1Δ ten1Δ	26 ± 6	5.9 ± 1.7	5.1 ± 1.9	5.9 ± 4.6	2.6 ± 1.6

Cultures were grown at 23° in −Trp liquid media for 3 days, and then the cell density was calculated by counting with a hemocytometer. Three hundred cells were plated on −Trp media and 10,000 cells plated on −Trp 5-FOA media. The number of colonies growing on the plates was determined after 7 days of growth at 23°. Multiple cultures were tested for each strain (n = 6). The plating efficiency was calculated for all strains, and the median fraction of cells that grow on −Trp 5-FOA relative to −Trp plates is expressed as a percentage. Thus, for ten1-101, only ∼2% of the colonies containing the pten1-101-TRP1 plasmid are viable on −Trp 5-FOA plates.