A strain, KH 5-7, with complex chromosomal rearrangements was detected by the production of white ascospores. In crosses heterozygous for KH 5-7, 60 to 90% of the ascospores were aborted and about 40% of discharged tetrads were 0:8 (black: white) type. Whereas in homozygous crosses 0 to 10% of the ascospores were aborted. The strain KH 5-7 included an interstitial translocation and a chromosomal break point on the left arm of linkage group (LG) I. The interstitial translocation was suggested to

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... lie between ser-3 and mating type locus (mt). The chromosomal break point was between nit-2 and leu-3 and the resulting chromosome fragment translocated to the right arm of LG VII in between un-l0 and nt. By the breakage of the right arm of LG VII, the resulting chromosome fragment translocated to the right arm of LG VI in between pan-2 and trp-2. The resulting chromosome fragment of the right arm of LG VI translocated to the left arm of LG I in between leu-3 and nit-2. The direction of attachment of the left arm of LG I to the right arm of LG VII was met-7, un-l0 (LG VII), break point nit-2, un-5 and f r (LG I).