FGSC #6137

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Reporting Genes: Sk-2;fl

Species: crassa

Allele: Borneo;P

Alternate Strain Number: 3315

Depositor: DDP

Linkage Group: III;IIR

Mating Type: a

Species Number: 10

Genetic Background: SL9

Opposite Mating Type: 3297

Deposit Sheet ↗

Genes

Locus	Cultural Requirements	Link Group	Type
Sk-2	III. Second-division segregation rare or absent. The killer allele Sk-2K recombines with his-7 (25%) but suppresses crossing over in the interval r(Sk-2)-1 to leu-1 (29% in controls). (1092). Sk-2K does not recombine with acr-7 (0/1800) or acr-2 (0/100,000) (B.C. Turner, personal communication). Kills ascospores of sensitive genotype after meiosis in crosses heterozygous for the killer allele Sk-2K. In Sk-2K x Sk-2S crosses (Killer x Sensitive), each ascus contains four inviable clear ascospores and four viable black ascospores that are SkK. Ascospores are not killed in SkK x SkK crosses (1092). Meiosis and postmeiotic mitosis appear normal by light microscopy. Sensitive spores first appear abnormal after one nuclear division in the ascospore. Sk-2S nuclei survive if included in the same ascospore with Sk-2(857). Originated in N. intermedia; introgressed into N. crassa. Most strains from nature are sensitive, but resistant strains of N. intermedia are common in some geographic areas, and two resistant strains of N. crassahave been found [see r(Sk-2)-1]. Strains resistant to Sk-2K are not necessarily resistant to Sk-3K. In Sk-2K x Sk-3K crosses, less than 1% of the ascospores are normal and viable (1092; B.C. Turner, personal communication). If Sk-2K and Sk-3K nuclei are included in the same ascospore, both nuclei survive and the spore is not killed (N.B. Raju, personal communication).	III	B
fl	IIR. Between ace-1 (5 to 11%) and trp-3 (3%) (816, PB). (613)No macroconidia (609). Highly fertile (612). Used routinely as the female parent in tests for chromosome rearrangements and for mating type (e.g., reference 801). The flsingle mutant produces few microconidia when dry; when wetted, sufficient microconidia are produced to have been used in early irradiation and mutation studies (614, 915); large numbers can be obtained under certain conditions; see reference 893. pe fl (46, 700) and fl;dn (806) double mutants produce abundant microconidia; the latter combination is highly fertile when homozygous. Photograph of microconidial formation (774); see also reference 893. Nuclear numbers in microconidia (46, 64, 478). Wall analysis (207). Immunoelectrophoretic pattern (784). Paradoxical high alcoholic glycolysis on nitrate medium (80). Deficiency of isocitrate lyase on acetate medium; see citations in reference 1088. When fl A and fl a strains are inoculated separately on crossing medium in plates, a double line of perithecia forms where they meet, similar to that accompanying barrage in Podospora (410, 414). fl ascospores from certain fl x fl+ crosses often germinate spontaneously (1127; N. B. Raju, personal communication). Allele C-1835 was called acon (717, 812).	IIR	B