Distinct functions of S. pombeRec12 (Spo11) protein and Rec12-dependent crossover recombination (chiasmata) in meiosis I; and a requirement for Rec12 in meiosis II

Table 1 Intergenic (crossover) recombination in rec12 mutants.

Genetic interval (chromosome)	No. tested^a	No. recombinant^a	Recombinant freq. (%)	cM^b	cM in wild-type^c	Fold reduction^c
A. *rec12-D15*
lys1 – his1 (I)	500	3	0.6	0.6	89	148
lys1 – ade4 (I)	500	8	1.6	1.6	284	177
his1 – ade2 (I)	500	2	0.4	0.4	57	142
his1 – tps19 (I)	500	2	0.4	0.4	143	357
ade2 – tps19 (I)	500	0	≤ 0.2	≤ 0.2	86	≤ 430
his4 – ade1 (II)	500	6	1.2	1.2	63	53
ade6 – arg1 (III)	500	1	0.2	0.2	97	486
					mean =	256 ± 154
B. *rec12-Y98F*
lys1 – his1 (I)	500	3	0.6	0.6	89	148
lys1 – ade4 (I)	500	17	3.4	3.5	284	81
his1 – ade2 (I)	500	1	0.2	0.2	57	285
his1 – tps19 (I)	500	1	0.2	0.2	143	715
ade2 – tps19 (I)	500	0	≤ 0.2	≤ 0.2	86	≤ 430
his4 – ade1 (II)	500	5	1.0	1.0	63	63
ade6 – arg1 (III)	500	4	0.8	0.8	97	121
					mean =	263 ± 220

^aSpore colonies were replica plated on non-selective and selective media; the number of colonies recombinant for each genetic interval are indicated. Diploid (potentially complementing) spore colonies were excluded from analysis. ^bGenetic distance calculated using the mapping function of Haldane [66]. ^cFold reduction in crossing over relative to published map distances in wild-type cells (NCBI Entrez Genome) [36]. The strains crossed were: WSP1826 × WSP1967; WSP1825 × WSP1962; WSP1967 × WSP1973; WSP1967 × WSP1973; WSP1967 × WSP1973; WSP2015 × WSP2018; WSP2026 × WSP2024; WSP2020 × WSP1966; WSP1670 × WSP1968; WSP1966 × WSP2027; WSP1966 × WSP2027; WSP1966 × WSP2027; WSP2014 × WSP2011; WSP1809 × WSP2028. Strain genotypes are provided in Table 3.