d : heterokaryon incompatibility-d
Used in early publications as a symbol for het-d.
da : dapple
IIL. Right of T(NM149). Linked to thr-3 (3%), probably to the right (1578, 1585, 1603).
Produces flecks of conidia on agar surface (1585). Conidia separate very easily (1958).
Dab-1 : Dead and buried-1 (Transposable element)
Cloned and sequenced: EMBL/GenBank Y14976; cosmid G14:3A.
A degenerate retrotransposon-like element of the gypsy class present in multiple copies in the genome. Lacks long terminal repeats and shows earmarks of RIP (177).
del : delicate
VIR. Between rib-1 (12%), pan-2 (6%) and os-9, T(OY329), trp-2 (0; 13%) (1603).
Growth is less profuse than wild type, with prolific hyphal branching flat on the agar and fine aerial growth at the top of a slant. Good scorability (1548).
The synonym Df: Deficiency is preferred. A single-gene deletion can be treated as an allele.
des : δ-subunit ATP synthase
Cloned and partially sequenced: EMBL/GenBank AI398451; EST W13F5.
Encodes the d-subunit of ATP synthase (1864).
Df(. . .): Deficiency
A segmental rearrangement having two or more contiguous genes missing. Deficiency is preferred to the synonymous term Deletion.
dgr-1 : deoxyglucose resistant-1
VL. Between rDNA, T(UK2-33), In(UK2-y)L and T(AR30), caf-1 (7%) (35, 1578).
Resistant to inhibition by 2-deoxy-D-glucose. Grows more slowly than wild type on standard medium but growth is initially faster than that of wild type on media with mono- or disaccharides plus deoxyglucose. Conidiation is precocious. The greatest differential growth in deoxyglucose is obtained with 0.1% cellobiose, trehalose, lactose, fructose, or galactose (35, 578, 1593). For convenient scoring, see ref. (1642).
dgr-2 : deoxyglucose resistant-2
I. Right of mat (15%), arg-1 (2%) (35). Linked to csp-1 (~1%) (573).
Resistant to inhibition by 2-deoxy-D-glucose and sorbose (35). Completely or partially resistant to carbon catabolite repression of glucoamylase, invertase, and glucose transport system II. Thermostability of invertase is altered. Lacks glucose transport system I.
dgr-3 : deoxyglucose resistant-3
Allelic with sor-4.
dgr-4 : deoxyglucose resistant-4
IR. Linked to al-2 (1%), probably to the left (35).
Resistant to inhibition by 2-deoxy-D-glucose and sorbose (35). Completely or partially resistant to carbon catabolite repression of glucoamylase, invertase, and glucose transport system II. Thermostability of invertase is altered. Glucose transport system I is enhanced.
dim : defective in methylation
The designation dim refers to trans-acting mutants showing reduction in or absence of DNA methylation at loci that are normally methylated (e.g., the y63 and z-h regions in Oak Ridge strains at the Fsr-63 and Fsr-33 loci). The designation does not refer to mutants showing reduced methylation when starved for methionine, such as eth-1 (at semipermissive temperatures) (660), and met and cys mutants starved for methionine (1732). It should be noted that DNA methylation in Neurospora is somewhat sensitive to growth conditions, and methylation levels can be increased, even in wild-type strains, by supplementation with methionine (662, 1885).
dim-1 : defective in methylation-1
III. Linked to mus-20, trp-1 (1885).
DNA methylation level is reduced by ~40% overall and multiple sites are affected, although to different extents. Mutant alleles may be partially dominant (660). Female sterility of dim-1 is complementable. Obtained by screening mutants that decrease the sensitivity of mus-20 to 5-azacytidine (662).
dim-2 : defective in methylation-2
VIIR. Between wc-1 and un-10, arg-10 (1094).
Specifies DNA methyltransferase (EC 2.1.1.-). Mutations abolish all detectable DNA methylation in vegetative cells but have no visible phenotype and do not affect fertility. Detected by screening for reduced methylation of the BamHI site in the 5S RNA pseudogene, Fsr63 (660, 661). RIP is not reduced by dim-2 (1885). dim-2 was used to demonstrate that quelling does not depend on DNA methylation (390), that DNA methylation indirectly prevents transcription elongation in Neurospora (1746), and that reversion to Am+ of Tad::am strains depends on DNA methylation (276).
dim-3 : defective in methylation-3
VR. Between am and inl (861).
Methylation is reduced at all of several methylated loci that were examined. Origin same as for dim-2 (660).
dim-4 : defective in methylation-4
IIR. Linked to arg-12, aro-1, ure-3 (812).
Reduces RIP frequency, unlike dim-2 (1885). Obtained in a visual screen for reduced RIP, using a pan-2 duplication (812).
Dip-1 : Diploid ascospores-1
IIIR. Between ro-2 (7%) and phe-2 (1%) (1322).
The mutant is vegetatively indistinguishable from wild type. Crosses heterozygous for Dip-1 typically give about two-thirds abnormal asci, most commonly with four ascospores but not uncommonly with eight. Other asci have three spores, or two, or one giant spore. The ascospores in asci with fewer than four spores are often misshapen and usually do not germinate. Surprisingly, Dip ´ Dip crosses give almost entirely eight-spored asci. Hence, Dip is not simply ascus-dominant in the usual sense. Spores from eight-spored asci are always haploid, and the Dip segregants can only be identified by progeny testing. Individual spores from four-spored asci generally give rise to cultures that are self-fertile because they are heterozygous or heterokaryotic for mat. When a four-spored ascus is heterozygous for multiple markers, a germinated ascospore gives rise to a culture in which the diploidy quickly breaks down, resulting in a complex heterokaryon. Many kinds of mitotic segregants can be isolated from the conidia of such a culture. Cytologically, the nuclei giving rise to ascospores are clearly of higher ploidy than haploid, but the exact number of chromosomes cannot be distinguished (1683). Crosses to Dip can shelter sexually lethal mutant genes such as Asm-1 and enable them to be recovered from crosses (1322).
dir : dirty
IR. Right of pa (37%) (1200).
Conidia are few and misshapen. A yellowish exudate may be produced (1201). Photograph (1200). One of the first markers to be mapped. Possibly os-1. Stock lost.
dn : dingy
IVR. Linked to rug (1%). Right of pyr-2 (4%) (1369, 1585).
Produces gray patches of microconidia in addition to macroconidia (1369). On glycerol complete medium, orange conidia are abundant at top of slant, with “dingy” growth on the flat surface below. Growth is slower than normal. The double mutant fl; dn produces abundant microconidia, similar to pe fl. Microconidia from fl; dn were found to be less viable, however (865). fl; dn is fully fertile in homozygous crosses (1584). For this reason, it may be preferred to pe fl as a microconidiating strain.
DNA repair mutants
See mei-2, mei-3, mus, nuh, phr, upr, uvs. Reviewed (946, 1838).
do : doily
VIIL. Linked to spco-4 (<1/400) (1592). Left of nic-3 (1%; 3%) (587, 1585).
Growth is restricted, colonial, and at 4% of the wild-type rate [(587); D. R. Stadler, cited in ref. (1585)]. Cell-wall galactosamine is 0.5% of the wild-type level, UDPGalNAc content is 3%, and the specific activity of UDPGlcNAc-4-epimerase in cell extracts is 20%. Partial back-mutations can differentially affect cell-wall and alcohol-soluble galactosamines, indicating pleiotropy (587). Cell-wall peptides are reduced in amount and have an altered DEAE elution profile (2249).
dot : dot
IR. Linked to ad-9 (0/44), right of thi-1 (2%) (1592).
Growth is colonial (1585) and more restricted on glycerol complete medium than on minimal. A possible maternal effect is seen in dot+ progeny from heterozygous crosses (1546).
dow : downy
IIIR. Between ty-1 (21%), un-17 (23%), T(AR17)L and T(AR17)R, erg-3 (10%, 14%). Linked to acu-7 (0/72), ro-11 (0/63) (1578, 1582, 1589, 1592).
Conidia are formed on a soft, matty mycelium that covers the agar in a slant (1592). An excellent marker with good viability, fertility, and scorability.
Dp(. . .) : Duplication
A rearrangement having two or more genes duplicated, either in tandem or ectopically. Strains duplicated for specific segments can be obtained as a major class of progeny from crosses heterozygous for insertional or quasiterminal rearrangements or from intercrosses between rearrangements having breakpoints appropriately positioned in the same two chromosome arms or in the same arm. For theory and applications, see ref. (1566). For information on individual duplications, see ref. (1578). See figure entitled “Duplication coverage.” Mapping by duplication coverage was pioneered by Dorothy Newmeyer in a paper (1475) that described the first Neurospora inversion, showed that one of its breakpoints is genetically terminal, and described the partial-diploid (duplication) progeny that result from crossing over when the inversion is heterozygous. The inversion was used in crosses to determine whether linked markers were located inside or outside the duplicated segment. The method was extended by using other duplication-generating rearrangements (1592), including both insertional and terminal translocations. Growth of duplication progeny was shown by Newmeyer to be greatly inhibitied when they were heterozygous for alleles at an included vegetative incompatibility locus. Duplications thus provided a practical way for identifying individual het genes. Use of the method is illustrated in refs. (1560) and (1566).
DUPLICATION COVERAGE Segments of the N. crassa genome that can be obtained as
viable nontandem duplications in progeny of crosses
heterozygous for insertional or quasiterminal chromosome rearrangements. Numbers to the right
of each dashed line
identify the rearrangement used to obtain duplications for the indicated segment. Genes that
bracket breakpoints are
shown, together with a few key markers for orientation, but most markers have been omitted.
The figure does not
show segments that can be obtained as duplications from overlapping rearrangements. The
duplications shown here, and the
rearrangements that produce them, have been used for determining dominance and dosage in
relating physical maps to genetic maps
obtaining genetically defined truncated chromosomes
studying chromosome instability (
identifying and manipulating vegetative incompatibility genes
and obtaining mutations by RIP
Reproduced from ref. (1578 ).
dr : drift
VIIR. Between for (3%) and T(5936), arg-10 (12%) (1578, 1580, 1604).
Conidia are formed in dense masses at the top of a slant. Growth elsewhere is flat on the agar surface. Good scorability (1604). Called mo(P1163).
dys-1 : deoxyhypusine synthase-1
Cloned and sequenced: Swissprot DHYS_NEUCR, EMBL/Genbank U22400.
Specifies the enzyme eukaryotic initiation factor 5A-deoxyhypusine synthase (EC 18.104.22.168) (2051). Enzyme purification (2052). See eif5A.
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