TABLE 6.

Mus81 is essential for generating crossovers associated with M-pal-dependent Ade⁺ convertants

	Parental genotypea		Ade+ recombinant/106 viable sporesb
Cross series	mus81	rec12	SI × 52	M-pal × 52
A. Gene conversion at ade6
19	+	+	185 ± 20	1260 ± 100
20	Δc	+	NAd	NAd
21	+	Δ152	8 ± 3	410 ± 65
22	Δ	Δ152	2	140 ± 45
Parental genotypef		% among Ade+ spores
NCOg		COg
Cross	rec12	mus81	P1	P2	R1	R2	Total Ade+ tested
B. Crossovers among the M-pal-dependent Ade+ convertantse
23	Δ152	+	58.6	3.3	36.9	1.2	336
24	Δ152	Δ	88.4	4.4	5.8	1.3	292

^aStrains with either ade6-3034 (SI) or ade6-3036 (M-pal) were crossed with strain GP3813 (relevant genotype: h⁻ ade6-52 rec12Δ mus81Δ). Crosses were homozygous for the indicated mutations or heterozygous for the indicated wild-type (+) alleles.

^bValues are the means of four independent experiments ±SEM. For cross series 22 (SI × 52), the total Ade⁺ recombinants obtained was divided by the combined total viable spores (from the four experiments). Crosses were performed at 25°.

^cmus81::kanMX6 (Δ) is a deletion of the mus81 ORF (Boddy et al. 2000).

^dNot available; the very low spore yield precluded reliable measurement of the Ade⁺ recombinant frequency.

^eSelected Ade⁺ convertant spore colonies were classified according to configuration of the flanking markers ura4⁺-aim and tps16 (Figure 1B). The parental (NCO) configurations were P1 (ade6-3036 tps16⁺), corresponding to parents GP4182 and GP4183, and P2 (ura4⁺-aim ade6-52 tps16-23), corresponding to parents GP4198 and GP4199. The recombinant (CO) configurations were R1 (ura4⁺-aim tps16⁺) and R2 (tps16-23).

^fCrosses were homozygous for the rec12 and mus81 alleles.

^gNCO, noncrossover; CO, crossover.