TABLE 4

Frequencies of 3:1 segregation

		Predicted % of undiagnosed false tetrads	% 3:1 segregation^c
Strain^a	Total tetrads^b	Predicted % of undiagnosed false tetrads	CAN1	URA3	HOM3	TRP2
Chromosome V
TID1	1409	0.8	0.8/0.7	0.3/0.2	0.6/0.5	1.4/1.3
tid1-pTID1	1222	0.4	1.1/1.0	0.6/0.5	0.6/0.6	1.6/1.5
TID1 combined	2631	0.6	0.9/0.8	0.4/0.3	0.6/0.5	1.5/1.4
tid1	1118	2.9	2.4/1.8^*	1.4/0.8	1.1/0.8	3.2/2.8^*
		Predicted % of undiagnosed false tetrads	% 3:1 segregation^c
Strain^a	Total tetrads^b	Predicted % of undiagnosed false tetrads	MAT	LEU2	URA3

Chromosome III
TID1	1250	3.1	1.3/0.2^d	6.4/6.2	1.8/1.5
tid1	1320	1.7	1.8/1.2^*	6.4/6.2	1.5/1.3
DMC1-YEpRAD54	1275	0.4	0.7/0.5	4.5/4.5	0.9/0.8
dmc1Δ-YEpRAD54	1362	0.6	0.4/0.2	7.6/7.5^*	0.7/0.6

Postmeiotic segregation was not detected in this experiment. Numbers presented are sums of the frequencies of 3⁺:1^- and 1⁺:3^- tetrads.
↵^a See footnotes a and b of Table 2 for names of strains used and marker locations.
↵^b Number of tetrads dissected minus the number of tetrads that were diagnostically false. The predicted percentage of undiagnosed false tetrads was calculated as [(N_f2 + N_N3) - (N_m3:1 + N_N4:0)]/Total × 100 (see appendix).
↵^c Percentages of observed frequencies/percentages corrected for the contribution of false tetrads (see appendix) are shown. ^*, the corrected value of 3:1 frequency for a mutant is significantly different from that of the wild-type control on the basis of Fisher’s exact test.
↵^d The large correction factor required makes this value less reliable than other estimates (see text).