TABLE 3

Analysis of coincident crossovers in adjacent intervals

	Total tetrads	Single intervals^b		Adjacent intervals		Observed
Strain^a	Total tetrads	URA3-LEU2	LEU2-MAT	Observed^c	Expected^d	expected	P value^e
TID1	1141	0.278	0.543	0.106	0.151	0.70	0.0001
tid1	1201	0.156	0.609	0.096	0.095	1.01	0.85
DMC1-YEpRAD54	1208	0.228	0.559	0.081	0.127	0.64	<0.00001
dmc1Δ-YEpRAD54	1249	0.158	0.510	0.087	0.081	1.07	0.37

↵^a See column 1 of Table 1 for names of strains used.
↵^b Frequency of T plus NPD tetrads for interval indicated.
↵^c Observed frequency of tetrads that are either T or NPD for both the URA3-LEU2 and the LEU2-MAT intervals.
↵^d “Expected” is the product of the frequencies given for the URA3-LEU2 interval and the LEU2-MAT interval.
↵^e P values reflect the likelihood that the difference between the expected and observed frequencies is attributable to chance as determined by a χ² test.