DOMINANT-AND-RECESSIVE EPISTASIS IN A HOMEOTIC MOSQUITO MUTANT

Folowing selection for 15 generations a pure strain of a homeotic mutant spur was isolated from a Brazilian population of the mosquito Culex pipiens fatigans. Monohybrid crosses showed a 13:3 segregation indicating dominant-and-recessive epistasis for wild-type vs. spur. This implies that a dominant allele at one locus and a recessive at the other interact to produce the mutant phenotype. Dihybrid crosses with linkage group II markers yellow and ruby gave 39:13:9:3 ratios indicating independent segregation. However, the dihybrid cross with linkage group I marker maroon showed a highly significant departure from 39:13:9:3 ratio. Data available indicate that the phenotype spur is controlled by a dominant epistat in linkage group III and a recessive epistat (approximately 31.9 crossover units from maroon) in linkage group I.

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Genetics of the tsetse fly Glossina morsitans submorsitans Newstead (Diptera: Glossinidae): further mapping of linkage groups I, II, and III

Canadian Journal of Zoology ◽

10.1139/z99-092 ◽

1999 ◽

Vol 77 (8) ◽

pp. 1309-1313 ◽

Cited By ~ 2

Author(s):

R H Gooding ◽

C M Challoner

Keyword(s):

Linkage Group ◽

X Chromosome ◽

Aldehyde Oxidase ◽

Female Offspring ◽

Tsetse Fly ◽

Glossina Morsitans ◽

Group Iii ◽

Glossina Morsitans Submorsitans ◽

Group I ◽

Group Ii

Standard mapping procedures were used to map four loci in linkage group I (the X chromosome), two loci in linkage group II, and two loci in linkage group III of Glossina morsitans submorsitans. In the presence of the allele Srd (the distorter allele favoring production of female offspring), no recombination occurred between any of the following loci: Pgm (phosphoglucomutase), wht (white eye color), Est-X (a thoracic esterase), and Sr (sex-ratio distortion). However, in the absence of Srd (i.e., in females homozygous for Srn, the allele that permits males to sire both female and male offspring in approximately equal numbers), the loci Pgm and wht were separated by 23 ± 4.0% recombination (map distance). These results indicate that ourG. m. submorsitans strains carry two forms of the X chromosome, designated XA and XB. In support of this interpretation, two lines of G. m. submorsitans were established: in both lines, males with wild-type eyes sired families that were almost exclusively female, while males with white eyes sired families having males and females in approximately equal numbers. Two loci, Ao (aldehyde oxidase) and Est-1 (a thoracic esterase) were separated by 6.1 ± 2.3% recombination in linkage group II, and two loci, Mdh (malate dehydrogenase) and Pgi (phosphoglucose isomerase), showed 51.9 ± 4.9% recombination in linkage group III.

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NEUROSPORA TREHALASE AND ITS STRUCTURAL GENE

Genetics ◽

10.1093/genetics/110.2.217 ◽

1985 ◽

Vol 110 (2) ◽

pp. 217-227

Author(s):

Christopher White ◽

Deborah B Lee ◽

Stephen J Free

Keyword(s):

Molecular Weight ◽

Linkage Group ◽

Structural Gene ◽

Gene Mutations ◽

Free Medium ◽

Wild Type ◽

Group I ◽

Normal Wild Type

ABSTRACT We have isolated Neurospora trehalaseless mutants and mapped the trehalase structural gene to linkage group I. The structural gene mutations not only affect thermostability and other characteristics of the enzyme but also affect the production of an inhibitor of the wild-type trehalase. The inhibitor appears to be the mutant trehalase. We suggest that the mutant subunits act as inhibitors by entering into the multimeric forms of the enzyme and altering the ability of the normal wild-type subunits to catalyze the cleavage of trehalose.—Wild type trehalase has been purified to near homogeneity, and its characteristics have been studied. It was purified as a tetramer, with each subunit having a molecular weight of 88,000.—We have studied the regulation of trehalase and found the production of trehalase to be glucose repressible. Cells begin to produce trehalase 60 min after being transferred to glucose-free medium.

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A comparative genetical study on DDT resistance in adults and larvae of the mosquito Aedes aegypti L

Genetics Research ◽

10.1017/s0016672300010971 ◽

1967 ◽

Vol 10 (3) ◽

pp. 219-228 ◽

Cited By ~ 17

Author(s):

R. J. Wood

Keyword(s):

Linkage Group ◽

Developmental Stages ◽

Major Gene ◽

Group Iii ◽

Group I ◽

Fourth Larval Stage ◽

Ddt Resistance ◽

Group Ii ◽

The Difference ◽

Two Stages

Inheritance of DDT resistance has been studied in crosses between the highly resistant ‘T’ strain of A. aegypti (constituted by inbreeding from the TRINIDAD DDT-resistant stock) and the ‘64’ susceptible strain.Larval DDT resistance derives from a major gene RDDT1 on linkage group II, the order being RDDT1–s–y. Linkage group III may also contribute to larval resistance. Linkage group I makes no contribution.Adult DDT resistance derives from a major gene RDDT2, 18·2 ± 2·1 units from the market blt on linkage group III. Linkage group II has no influence on adult resistance.Selection with DDT to retain only RDDT1/+ segregants in larvae of backcrosses RDDT1/+×+/+ did not increase resistance in resulting adults, confirming the difference in genetic mechanism at the two stages.The F1 progenies from reciprocal crosses between ‘T’ and ‘64’ differed slightly but significantly in larval resistance, modifying the influence of the major gene RDDT1 in the heterozygote.The early developmental stages of the RDDT1/+ phenotype (up to the fourth larval stage) were more viable than the +/+ phenotype in backcross segregation. The difference in mortality probably exceeded 30%.

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REVERSAL OF A NEUROSPORA TRANSLOCATION BY CROSSING OVER INVOLVING DISPLACED rDNA, AND METHYLATION OF THE rDNA SEGMENTS THAT RESULT FROM RECOMBINATION

Genetics ◽

10.1093/genetics/114.3.791 ◽

1986 ◽

Vol 114 (3) ◽

pp. 791-817

Author(s):

David D Perkins ◽

Robert L Metzenberg ◽

Namboori B Raju ◽

Eric U Selker ◽

Edward G Barry

Keyword(s):

Linkage Group ◽

Distal Portion ◽

Nucleolus Organizer ◽

Rrna Genes ◽

Molecular Evidence ◽

Crossing Over ◽

Wild Type ◽

Type Locus ◽

Group I ◽

Chromosome Sequence

ABSTRACT In translocation OY321 of Neurospora crassa, the nucleolus organizer is divided into two segments, a proximal portion located interstitially in one interchange chromosome, and a distal portion now located terminally on another chromosome, linkage group I. In crosses of Translocation x Translocation, exceptional progeny are recovered nonselectively in which the chromosome sequence has apparently reverted to Normal. Genetic, cytological, and molecular evidence indicates that reversion is the result of meiotic crossing over between homologous displaced rDNA repeats. Marker linkages are wild type in these exceptional progeny. They differ from wild type, however, in retaining an interstitial block of rRNA genes which can be demonstrated cytologically by the presence of a second, small interstitial nucleolus and genetically by linkage of an rDNA restriction site polymorphism to the mating-type locus in linkage group I. The interstitial rDNA is more highly methylated than the terminal rDNA. The mechanism by which methylation enzymes distinguish between interstitial rDNA and terminal rDNA is unknown. Some hypotheses are considered.

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Enhancers of conidiation mutants in Aspergillus nidulans.

Genetics ◽

10.1093/genetics/137.1.79 ◽

1994 ◽

Vol 137 (1) ◽

pp. 79-85

Author(s):

D H Gems ◽

A J Clutterbuck

Keyword(s):

Linkage Group ◽

Aspergillus Nidulans ◽

Double Mutant ◽

Slight Modification ◽

Temperature Sensitive ◽

Permissive Temperature ◽

Wild Type ◽

Group V ◽

Group I

Abstract Mutants at a number of loci, designated sthenyo, have been isolated as enhancers of the oligoconidial mutations at the medA locus. Two loci have been mapped: sthA on linkage group I, and sthB on linkage group V. Two probable alleles have been identified at each locus but two further mutants were unlinked to either sthA or sthB. Neither sthA nor sthB mutants have conspicuous effects on morphology on their own, nor could the sthA1 sthB2 double mutant be distinguished from wild type. Mutants at both loci also interact with the temperature-sensitive brlA42 mutant at the permissive temperature to give a phenotype described as "Abacoid." sthA1 also induces a slight modification of the phenotype of an abaA mutant. We conclude that sthenyo genes act mainly at the phialide stage of conidiation. We also describe the isolation of new medA mutants arising spontaneously as outgrowths on brlA42 colonies.

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The regulation of NADL-glutamate dehydrogenase inAspergillus nidulans

Genetics Research ◽

10.1017/s0016672300014713 ◽

1974 ◽

Vol 23 (1) ◽

pp. 119-124 ◽

Cited By ~ 1

Author(s):

J. R. Kinghorn ◽

J. A. Pateman

Keyword(s):

Amino Acids ◽

Linkage Group ◽

Carbon Source ◽

Glutamate Dehydrogenase ◽

Aspergillus Nidulans ◽

Dehydrogenase Activity ◽

Carbon Sources ◽

Wild Type ◽

Group Iii ◽

Glutamate Dehydrogenase Activity

SummaryWild-type cells ofAspergillus nidulanshave undetectable NADL-glutamate dehydrogenase activity when utilizing glucose and high levels of NADL-glutamate dehydrogenase when utilizing certain amino acids as sole carbon sources.A mutant, designatedgdhCl, has appreciable NAD-GDH activity when utilizing glucose as a carbon source. ThegdhC1mutation is semi-dominant and is located in linkage group III.

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Formal and physiological genetics of ascospore colour in Aspergillus nidulans

Genetics Research ◽

10.1017/s0016672300003621 ◽

1963 ◽

Vol 4 (2) ◽

pp. 276-283 ◽

Cited By ~ 12

Author(s):

D. Apirion

Keyword(s):

Linkage Group ◽

Aspergillus Nidulans ◽

Nitrous Acid ◽

Group Iv ◽

Locus Symbol ◽

Parental Genotype ◽

Wild Type ◽

Uv Treatment ◽

Group I ◽

Group Ii

By nitrous acid or UV treatment ascospore colour mutants of two kinds, blue and colourless, were obtained in Aspergillus nidulans (wild-type has red ascospores). Four blue mutants were located in linkage group II within 0·5 unit of one another (locus symbol: b11). Of the colourless mutants, four were located in linkage group I within one unit of one another (locus symbol: c16), and one in linkage group IV (locus symbol: c14). In diploids the mutants were recessive. Colourless was epistatic to blue.In crosses these characters behaved as ‘non-autonomous’ both in the ascospores and in the asci; all the ascospores of the asci in one perithecium as well as the perithecium wall were of the same colour. In crosses between strains with blue perithecia and strains with colourless perithecia, red, blue and colourless perithecia were found; each type included both crossed and selfed perithecia. Red selfed perithecia were of either parental genotype but blue or colourless selfed perithecia always had the corresponding genotype.The phenotype of the perithecium (perithecial wall and ascospores) is considered to be determined by the homo- or heterokaryotic constitution of the protoperi-thecium which gave origin to it.

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Uterine Characteristics of Prepubertal Gilts at Fixed Body Weight

Annals of Animal Science ◽

10.2478/aoas-2018-0058 ◽

2019 ◽

Vol 19 (2) ◽

pp. 373-381

Author(s):

Hanna Jankowiak ◽

Wojciech Kapelański ◽

Maria Bocian

Keyword(s):

Body Weight ◽

Reproductive Tract ◽

Great Variability ◽

Morphometric Parameters ◽

Uterine Weight ◽

Factors Affecting ◽

Group Iii ◽

Group I ◽

Size Variability ◽

Selection For

AbstractReproduction is one of the most important factors affecting the efficiency of animal production. Within the scope of uterine capacity and other morphometric parameters, the objective of this study was to evaluate the size variability of uterus dissected from prepubertal gilts. The research was conducted on 100 PLW gilts and 100 PL gilts at a pig testing station. After slaughter, the reproductive tract was dissected, and each element was measured and weighed. The obtained results were combined and analyzed in three groups differentiated by uterine capacity: I, II and III. Group I consisted of gilts with a uterine capacity below 115 cm3 (n=69); group II comprised gilts with a uterine capacity between 115 and 175 cm3 (n=85); uterine capacity in group III was above 175 cm3 (n=46). Ontogenesis of the reproductive tract showed great variability with respect to the uterine capacity of gilts of both breeds. Uterine weight with and without ligament was different between the analyzed groups of PLW gilts (P<0.01), and also between the groups of PL gilts (P<0.01; P<0.05). The uterine horns of the PLW gilts in group I were slightly longer than in the PL gilts (90.76 cm vs. 84.20 cm; P<0.05). A slightly higher variability of uterine capacity was observed with respect to the PLW gilts (80.92 cm3 to 243.13 cm3), as compared with the PL gilts (92.61 cm3 to 235.23 cm3). The determined uterine capacity was significantly correlated with all parameters of uterine size (P<0.01), apart from the length of the uterus and cervix in PLW gilts. The proportion between the uterine weight and the length of its horns, which characterizes the thickness of uterine walls, was significantly correlated with the length of uterine horns only in PL gilts (r=0.382**). This study may be used to forecast the potential fertility of related females (littermate gilts and their daughters); it may also be used in sow selection for litter size.

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The effect of cholesterol on cancer growth and metastasis: Experimental study with LDL receptor knockout mice.

Journal of Clinical Oncology ◽

10.1200/jco.2013.31.15_suppl.e22071 ◽

2013 ◽

Vol 31 (15_suppl) ◽

pp. e22071-e22071

Author(s):

Daniel Pu ◽

Yuqi Cui ◽

Zhenzhen Liu ◽

Sampath Parthasarathy ◽

Xuefeng Bai ◽

...

Keyword(s):

Weight Loss ◽

Weight Gain ◽

Ldl Receptor ◽

Cancer Growth ◽

Wild Type ◽

Group Iii ◽

Cholesterol Levels ◽

Group I ◽

High Lipid ◽

Ldl Receptor Knockout Mice

e22071 Background: Cholesterol is an essential component for normal cell growth. However, epidemiological studies show cholesterol levels may be associated with cancer incidence. The Multiple Risk Factor Intervention Trial reported a significant inverse relationship between cholesterol levels and lung cancer. The effects of cholesterol on cancer growth and metastasis have not been established. The aim of the present study was to determine if cholesterol alters cancer growth or metastasis. Methods: The study used 48 wild-type mice and 18 LDL receptor knockout mice (LDLR-/-). Mice were randomized into 3 groups: Group I (wild-type mice fed normal chow, n=23); Group II (wild-type mice fed high lipid chow, n=25); Group III (LDLR-/- mice fed high lipid chow, n=18). Human melanoma cells were injected subcutaneously for the assessment of growth and intravenously for metastasis. Mice were followed for 4 weeks. At the end of the study, mice were weighed and autopsy was performed. Melanoma weight, metastasis, and blood cholesterol levels were evaluated. Data was analyzed using One-way ANOVA and Chi-square. Results: LDL-cholesterol level was significantly higher in Group III than Group I (1103±472 vs.28±6; p<0.01). There was no significant difference in melanoma weight (2.74g ±1.77, 2.98g±1.98 vs. 2.18g±1.59, P=0.56) among the three subcutaneous injection groups. Lung metastasis was observed in all intravenous injection groups (11/11 vs. 10/10 vs. 8/8). There was no difference in melanoma weight or metastasis between male and female mice (P>0.05). There was no difference in net weight gain among the subcutaneous injection groups (4.12g±2.50 vs. 2.64g±2.79 vs. 3.66g±1.96, P=0.30). However, among the intravenous injection groups, weight gain was observed in Group II (2.78g±2.67) and Group III (2.36g±1.73) and weight loss in Group I (-0.32g±1.34, P<0.003). Conclusions: Cholesterol has no effect on melanoma growth or metastasis in mice. A high cholesterol diet may reduce weight loss in animals with metastatic melanoma. Further study is warranted to determine whether similar results exist in other types of cancers and to evaluate a possible beneficial effect of high lipid diets on patients with metastatic cancers.

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Characterization of the new osmotic mutants (os) which originated during genetic transformation inNeurospora crassa

Genetics Research ◽

10.1017/s0016672300017079 ◽

1977 ◽

Vol 29 (1) ◽

pp. 9-19 ◽

Cited By ~ 6

Author(s):

N. C. Mishra

Keyword(s):

Linkage Group ◽

Genetic Transformation ◽

Neurospora Crassa ◽

Wild Type ◽

Induced Mutation ◽

Group I ◽

Intragenic Complementation ◽

Inneurospora Crassa ◽

New Alleles

SUMMARYInositol independent (inl+) strains were obtained either as transformants following treatment of the inositol requiring (inl) strains ofNeurospora crassawith the wild-type DNA or as revertants without any DNA treatment. A significant number of the inositol-independent transformants were also found to have acquired additional mutations called osmotics (os) which made them unable to grow on 1 m-NaCl medium. None of the inositol-independent revertants were found to possess such osmotic mutations and their growth remained unaffected by the presence of NaCl. Many of the osmotic mutants described here were found to be new alleles of the previously knownos–1mutation on the linkage group I ofNeurospora crassa. The remainder were found to map at two new genetic loci designated asos-6andos-7; these loci were found to be closely linked toos–1. Among the new osmotic mutants onlyos-1andos-6mutants showed intragenic complementation. The mechanism of DNA-induced mutation during transformation is discussed.

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