FGSC #3332

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Reporting Genes: ad-3A al-2;cot-1;pan-2

Species: crassa

Allele: N24 Y112M38;C102(t);Y387-15.7

Depositor: TMO

Linkage Group: IR IR;IVR;VIR

Mating Type: A

Species Number: 10

ref1: Ong Mut Res 53:297-308 1978, https://doi.org/10.1016/0165-1161(78)90002-x

ref2: Ong et al Cancer Res 35:291-295 1975, https://cancerres.aacrjournals.org/content/canres/35/2/291.full.pdf

Deposit Sheet ↗

Genes

Locus	Cultural Requirements	Link Group	Type
ad-3A	IR. Between his-3 (1 to 2%) and ad-3B (0.1 to 0.7%) (271). Right of ure-4 (78). (482) Requires adenine or hypoxanthine (682). Blocked in interconversion of CAIR plus aspartate to SAICAR (348) (Fig. 8). Produces purple pigment, permitting direct visual selection (276, 682); see the ad-3B entry. Reduced interallelic fertility (407). No interallelic complementation (267; F.J. de Serres, personal communication). ad-3A and ad-3B are two genetically and functionally distinct loci separated by a short but functionally complex region of unknown but essential function (271, 407). They have been used intensively for quantitative genetic and molecular studies of mutation (for a review, see reference 35). Either forward mutation (e.g., reference 277) or reverse mutation (e.g., reference 772) can be measured precisely; the former is detected visually by purple pigment. Purple pigment has also been used to assess the effect of histidine and tryptophan on purine nucleotide synthesis (786). Alleles N23 and N24 have been used as mutagen testers. N23 reverts with agents that cause base pair substitutions; N24 reverts with agents that cause frameshifts (772). SK(ad-3A) is at or near ad-3A and may be a cryptic ad-3A allele. Does not require adenine. In SK(ad-3A)x ad-3Acrosses, the ad-3A progeny die; possibly SK(ad-3A) mutants fail to make enough adenine to support their growth (251). Translocations Y155M64 ad-3A (272; PB) and Y112M15 ad-3A(413) each have one breakpoint that is inseparable from ad-3A. Called complementation group A (264). "A" in the locus symbol does not refer to mating type.	IR	B
al-2	IR. Right of os-5 (<1%) and T(STL76). Left of arg-6(1%) and al-1 (797, 802, 808, 816, 818). Included in duplications from Tp(T54M94), confirming location left of arg-6(808). (482) Carotenoids absent or abnormal, but steroids produced (398). Blocked in microsomal fraction and defective in phytoene synthetase (445), a particulate enzyme (445 and references cited therein) (Fig. 9). Tracer experiments indicate a lesion between prephytoene pyrophosphate and phytoene (572). Alleles include those resulting in white and pale rose-white, e.g., 15300 and Y254MI65 (1042), and purple, e.g., MN58a (154). For complementation, see references 500 and 1041. Fine-structure mapping (500, 1042) needs reevaluation because of new information on the location of the arg-6 marker (797).	IR	B
cot-1	IVR. Between pan-1 (2%) and his-4 (1 to 6%) (692, 812, 816). Extremely colonial at 34°C, but completely normal growth, morphology, and fertility at 25°C and below. Linear growth is maximum at 24°C (374). Becomes colonial at 32°C; colonies from ascospores or conidia are viable and continue to grow slowly with dense branching, but do not conidiate. They quickly resume normal growth when shifted to a permissive temperature (692, 1068). Recessive in duplications (808); apparent dominance in heterokaryons (374) may have resulted from a shift in nuclear ratios. Used in studies of septation and branching (202), growth-inhibiting mucopolysaccharide (878, 879), and sulfate transport (641). Cell wall analysis (374). Growth is stimulated by lysine or arginine (0.1 mM) on glucose media at high temperatures (615). Because of high viability and tightly restricted growth at restrictive temperatures and normality at 25°C, cot-1 mutants have valuable technical applications. For example, crosses homozygous for cot-1 have been used in combination with sorbose for experiments with rec genes, where high-density ascospore platings are required for precise quantitative analysis of intralocus recombination (e.g., references 165, 997, and 1070). In another application, when shifted up after initial growth at the permissive low temperature, cot-1hyphae assume a "bottle brush" appearance with small side branches (692). This has been used to select uvs mutants by subsurface survival on UV-irradiated plates containing p-aminobenzoic acid (938; D.E.A. Catcheside, personal communication). cot-1 conidia or ascospores from cot-1 x cot-1crosses are used for replication in a protocol involving transfer by filter paper (615). For suppressors of cot-1, see gul.	IVR	B
pan-2	VIR. Right of rib-1 (<1 to 3%). Left of del (6%) and trp-2(11%) (140, 141, 143, 818, PB). Unable to convert ketovaline to ketopantoic acid (138, 140, 141). Used in major studies of intralocus recombination and complementation (140-143). pan-2ascospores remain white or pale if the crossing medium is not supplemented, even when the protoperithecial parent is pan-2+. Asci in which gene conversion has occurred at pan-2 can thus be recognized and isolated (1072, 1073); photographs (1072). For good recovery of pan-2progeny, crossing media should be supplemented with pantothenic acid (10 µg/ml) even when the protoperithecial parent is pan+. Called group B.	VIR	B