scholarly journals GENETIC ANALYSIS OF MATING-TYPE DIFFERENTIATION IN PARAMECIUM TETRAURELIA

Genetics ◽  
1977 ◽  
Vol 87 (4) ◽  
pp. 633-653
Author(s):  
Yves Brygoo
Keyword(s):  
Genetic Analysis ◽  
Mating Type ◽  
Geographical Origin ◽  
Cytoplasmic Inheritance ◽  
Mating Types ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Cytoplasmic Factors ◽  
Nuclear Change

ABSTRACT Whereas each of the two complementary mating types, O and E, of Paramecium tetraulrelia normally shows cytoplasmic inheritance, an abnormal heredity of mating type was observed in the progeny of crosses between two stocks of different geographical origin of Paramecium tetraurelia(stock 51 and stock 32). The modified pattern of mating-type inheritance was shown to result from the interaction of the two wild-type alleles at the locus mtD (mtD51 and mtD32), leading to a new differentiated state O*, different from the normal O and E states observed in both stock 51 and stock 32 cells. The genetic analysis of O* clones showed that the O* phenotype involves both a new heritable cytoplasmic state and possibly a nuclear change which can be transmitted through conjugation and segregates in a Mendelian fashion. All the data can be interpreted if the assumption is made that mating-type determination is achieved only by the commitment or noncommitment to the expression of mating-type E, and that this commitment may simply reflect the activation or nonactivation of the locus mtD, under the influence of one or two "cytoplasmic factors" including the product of the gene mtD itself.

scholarly journals GENETIC ANALYSIS OF MATING TYPE DIFFERENTIATION IN PARAMECIUM TETRAURELIA. II. ROLE OF THE MICRONUCLEI IN MATING-TYPE DETERMINATION

Genetics ◽  
1980 ◽  
Vol 94 (4) ◽  
pp. 951-959
Author(s):  
Y Brygoo ◽  
T M Sonneborn ◽  
A M Keller ◽  
R V Dippell ◽  
M V Schneller
Keyword(s):  
Genetic Analysis ◽  
Mating Type ◽  
Cytoplasmic Inheritance ◽  
Mating Types ◽  
Paramecium Tetraurelia ◽  
Macronuclear Development ◽  
Cytoplasmic Factors ◽  
Determining Factors

ABSTRACT The two complementary mating types, 0 and E, of Paramecium tetrauretia are normally inherited cytoplasmically. This property has generally been interpreted to indicate the presence of cytoplasmic factors that determine macronuclear differentiation towards 0 or E . In these macronuclear-cytoplasmic interactions, the micronuclei were held to be unbiased and the determination to be established in the course of macronuclear development. In order to ascertain whether the micronuclei were actually neutral, amicronucleate clones were needed and a method to produce them was developed. In crosses between amicronucleate clones and normal micronucleate clones, we have observed regular deviations from cytoplasmic inheritance: the commonest deviation is that most 0 amicronucleate cells become E when they receive a micronucleus from an E partner. The data can be interpreted by assuming that the micronuclei are predetermined and that the apparent "cytoplasmic" inheritance of the two mating types is due, in E cells, to E-determining factors present in the cytoplasm and in the nucleus; and, in 0 cells, to 0-determining factors present only or mainly in the nucleus.

scholarly journals Phenotypic and Genetic Analysis of “Chameleon,” a Paramecium Mutant With an Enhanced Sensitivity to Magnesium

Genetics ◽  
1997 ◽  
Vol 146 (3) ◽  
pp. 871-880
Author(s):  
Robin R Preston ◽  
Jocelyn A Hammond
Keyword(s):  
Genetic Analysis ◽  
Single Locus ◽  
Behavioral Analysis ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Ion Conductance ◽  
Membrane Excitation ◽  
Enhanced Sensitivity ◽  
Electrophysiological Analysis ◽  
Mutant Strains

Three mutant strains of Paramecium tetraurelia with an enhanced sensitivity to magnesium have been isolated. These new “Chameleon” mutants result from partial- or codominant mutations at a single locus, Cha. Whereas the wild type responded to 5 mm Mg2+ by swimming backward for 10–15 sec, Cha mutants responded with ∼30 sec backward swimming. Electrophysiological analysis suggested that this behavior may be caused by slowing in the rate at which a Mg2+-specific ion conductance deactivates following membrane excitation. This would be consistent with an observed increase in the sensitivity of Cha mutants to nickel poisoning, since Ni2+ is also able to enter the cell via this pathway. More extensive behavioral analysis showed that Cha cells also overresponded to Na+, but there was no evidence for a defect in intracellular Ca2+ homeostasis that might account for a simultaneous enhancement of both the Mg2+ and Na+ conductances. The possibility that the Cha locus may encode a specific regulator of the Mg2+- and Na+-permeabilities is considered.

scholarly journals GENES CONTROLLING MATING-TYPE SPECIFICITY IN PARAMECIUM CAUDATUM: THREE LOCI REVEALED BY INTERSYNGENIC CROSSES

Genetics ◽  
1983 ◽  
Vol 104 (1) ◽  
pp. 41-62
Author(s):  
Yuuji Tsukii ◽  
Koichi Hiwatashi
Keyword(s):  
Genetic Analysis ◽  
Mating Type ◽  
Pair Formation ◽  
High Fertility ◽  
Mating Types ◽  
Paramecium Caudatum ◽  
Multiple Alleles ◽  
Behavioral Marker ◽  
Species Pairs ◽  
Recessive Homozygote

ABSTRACT In mating interactions in Paramecium caudatum, initial mating agglutination is strictly mating-type specific, but subsequent conjugating pair formation is not mating-type specific. Using this nonspecificity of pair formation, intersyngenic (intersibling species) pairs were induced by mixing four mating types of two different syngens. To distinguish intersyngenic pairs from intrasyngenic ones, the behavioral marker CNR (Takahashi 1979) was mainly used. Clones of intersyngenic hybrids showed high fertility and thus made feasible a genetic analysis of syngenic specificity of mating type. The syngenic specificities of E (even) mating types were found to be controlled by co-dominant multiple alleles at the Mt locus, and those of O (odd) mating types by interactions of co-dominant multiple alleles at two loci, MA and MB. Clones of heterozygotes express dual mating types. Mt is epistatic to MA and MB, and thus O mating types can be expressed only in the recessive homozygote (mt/mt) at the Mt locus. In addition, at least one allele each at the MA and MB loci must have a common syngen specificity for the expression of O types. Thus, when MA is homozygous for one syngen and MB is homozygous for another syngen, no mating type is expressed.

MUTANTS WITH ALTERED Ca2+-CHANNEL PROPERTIES IN PARAMECIUM TETRAURELIA: ISOLATION, CHARACTERIZATION AND GENETIC ANALYSIS

Genetics ◽  
1984 ◽  
Vol 108 (3) ◽  
pp. 545-558
Author(s):  
Robert D Hinrichsen ◽  
Yoshiro Saimi ◽  
Ching Kung
Keyword(s):  
Genetic Analysis ◽  
Complementation Group ◽  
Phenotypic Change ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Cytoplasmic Factor ◽  
Wild Type Phenotype ◽  
Channel Properties ◽  
Ca2 Channels ◽  
F1 Generation

ABSTRACT Dancers are a group of mutants in Paramecium tetraurelia whose Ca2+ current inactivates poorly and are likely to be defective in the structure of their Ca2+ channels. These mutants show prolonged backward swimming in response to K+ and Ba2+ in the medium and were selected by this property in a galvanotactic trough. The dancer mutants are semidominant, and all isolated mutants belong to one complementation group; they are not allelic to any of the previously isolated behavioral mutants of P. tetraurelia. The phenotypic change from the homozygous parent to heterozygous F1 generation takes three to five fissions. There is no evidence of a cytoplasmic factor capable of converting the dancer to the wild-type phenotype, as has been demonstrated in the mutants pawn and cnr. We suggest that the dancer locus is a structural gene for the Ca2+ channel.

scholarly journals Frequency and Genetic Diversity of theMAT1Locus of Histoplasma capsulatum Isolates in Mexico and Brazil

2013 ◽  
Vol 12 (7) ◽  
pp. 1033-1038 ◽  
Author(s):  
Gabriela Rodríguez-Arellanes ◽  
Carolina Nascimento de Sousa ◽  
Mauro de Medeiros-Muniz ◽  
José A. Ramírez ◽  
Cláudia V. Pizzini ◽  
...  
Keyword(s):  
Mating Type ◽  
Internal Transcribed Spacer ◽  
Histoplasma Capsulatum ◽  
Geographical Origin ◽  
Soil Samples ◽  
The Other ◽  
Clinical Samples ◽  
Mating Types ◽  
Content Type ◽  
Type Strains

ABSTRACTTheMAT1-1andMAT1-2idiomorphs associated with theMAT1locus ofHistoplasma capsulatumwere identified by PCR. A total of 28 fungal isolates, 6 isolates from human clinical samples and 22 isolates from environmental (infected bat and contaminated soil) samples, were studied. Among the 14 isolates from Mexico, 71.4% (95% confidence interval [95% CI], 48.3% to 94.5%) were of theMAT1-2genotype, whereas 100% of the isolates from Brazil were of theMAT1-1genotype. EachMAT1idiomorphic region was sequenced and aligned, using the sequences of the G-217B (+ mating type) and G-186AR (− mating type) strains as references. BLASTn analyses of theMAT1-1andMAT1-2sequences studied correlated with their respective + and − mating type genotypes. Trees were generated by the maximum likelihood (ML) method to search for similarity among isolates of eachMAT1idiomorph. AllMAT1-1isolates originated from Brazilian bats formed a well-defined group; three isolates from Mexico, the G-217B strain, and a subgroup encompassing all soil-derived isolates and two clinical isolates from Brazil formed a second group; last, one isolate (EH-696P) from a migratory bat captured in Mexico formed a third group of theMAT1-1genotype. TheMAT1-2idiomorph formed two groups, one of which included twoH. capsulatumisolates from infected bats that were closely related to the G-186AR strain. The other group was formed by two human isolates and six isolates from infected bats. Concatenated ML trees, with internal transcribed spacer 1 (ITS1) -5.8S-ITS2 andMAT1-1orMAT1-2sequences, support the relatedness ofMAT1-1orMAT1-2isolates.H. capsulatummating types were associated with the geographical origin of the isolates, and all isolates from Brazil correlated with their environmental sources.

scholarly journals ISOGENIC STRAINS OF PHYCOMYCES BLAKESLEEANUS SUITABLE FOR GENETIC ANALYSIS

Genetics ◽  
1983 ◽  
Vol 105 (4) ◽  
pp. 873-879
Author(s):  
M I Alvarez ◽  
A P Eslava
Keyword(s):  
Genetic Analysis ◽  
Mating Type ◽  
Type Strain ◽  
Wild Type ◽  
Tetrad Analysis ◽  
Phycomyces Blakesleeanus ◽  
Isogenic Strains ◽  
Type Strains

ABSTRACT The progeny of crosses between wild-type strains of Phycomyces usually do not exhibit all of the expected genotypes from meiosis. By backcrossing, we have isolated a new (+) mating-type strain, A56, which is nearly isogenic with the (-) wild-type NRRL1555 commonly used in Phycomyces research. Tetrad analysis of the backcrosses shows that meiosis becomes more regular as the parental (+) and (-) strains become more isogenic. In our two-factor crosses with unlinked markers, the regularity of meiosis is measured as the percent of reciprocal ditypes plus tetratypes in the progeny. We have shown that this percentage increases from about 15% for crosses between nonisogenic parents to 90% in the eighth backcross. The results indicate that routine, reliable recombination analyses are possible in P. blakesleeanus.

scholarly journals A Mendelian Mutation Affecting Mating-Type Determination Also Affects Developmental Genomic Rearrangements in Paramecium tetraurelita

Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 191-202 ◽  
Author(s):  
Eric Meyer ◽  
Anne-Marie Keller
Keyword(s):  
Mating Type ◽  
Maternal Inheritance ◽  
Germ Line ◽  
Molecular Model ◽  
Genomic Rearrangements ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Genetic Context ◽  
Pleiotropic Mutation

Abstract In Paramecium tetraurelia, mating type is determined during the differentiation of the somatic macronucleus from a zygotic nucleus genetically competent for both types, O and E. Determination of the developing macronucleus is controlled by the parental macronucleus through an unknown mechanism resulting in the maternal inheritance of mating types. The pleiotropic mutation mtFE affects macronuclear differentiation. Determination for E is constitutive in mutant homozygotes; a number of unrelated mutant characters are also acquired during development. We have examined the possibility that the mutation causes a defect in the developmental rearrangements of the germ-line genome. We show that the excision of an IES (internal eliminated sequence) interrupting the coding sequence of a surface antigen gene is impaired in the mutant, resulting in an alternative macronuclear version of the gene. Once established, the excision defect is indefinitely transmitted across sexual generations in the cytoplasmic lineage, even in a wild-type genetic context. Thus, the processes of mating-type determination and excision of this IES, in addition to their common sensitivity to the mtFE mutation, show a similar maternal inheritance of developmental alternatives in wild-type cells, suggesting a molecular model for mating-type determination.

scholarly journals GENETICS OF CHEMICAL INDUCTION OF CONJUGATION IN PARAMECIUM AURELIA

Genetics ◽  
1974 ◽  
Vol 76 (4) ◽  
pp. 703-714
Author(s):  
Donald L Cronkite
Keyword(s):  
Mating Type ◽  
Recessive Gene ◽  
Mating Types ◽  
Wild Type ◽  
Chemical Induction ◽  
Single Mating ◽  
In Cells

ABSTRACT Certain stocks of P. aurelia, syngen 8, could not be induced to conjugate in a solution (KCl + acriflavine + calcium-poor conditions) which was effective in inducing conjugation in other species of Paramecium as well as in other stocks of syngen 8. Both stocks could conjugate by interaction with cells of complementary mating type. Breeding analysis shows that each of the two stocks is homozygous for a recessive gene that blocks induction of conjugation by the KCl-acriflavine solution. These two genes are neither allelic nor linked. Analyses of the phenotypes of the two uninducibles and the wild type were carried out by attempting to induce mating in cells of a single mating type by exposing them to detached mating-reactive cilia from cells of complementary mating type and to the KCl-acriflavine solution, either sequentially or simultaneously. The results confirm the conclusions of others that there is at least one unique step in chemical induction not shared with induction by interaction of complementary mating types. But the results also indicate that there is more than one unique step in chemical induction and that the effects of the two genes described here operate during different periods of the hour required for chemical induction.

scholarly journals Genetic studies inEudorina

1968 ◽  
Vol 11 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Nawin C. Mishra ◽  
S. F. H. Threlkeld
Keyword(s):  
Genetic Analysis ◽  
Mating Type ◽  
Single Gene ◽  
Female Parent ◽  
Cross Resistance ◽  
Nutritional Requirement ◽  
Wild Type ◽  
Type Locus ◽  
S 100 ◽  
High Concentrations

A formal genetic analysis of the heterothallic, colonial green algaEudorina eleganshas been described. Wild-type strains were found to be sensitive to different drugs when grown on minimal agar containing very low concentrations of these drugs. Mutant strains resistant to high concentrations of drugs have been isolated. These aremsr-500(resistant to 500 μg/ml of DL-methionine-DL-sulfoximine),ery-r-100(resistant to 100 μg/ml of erythromycin) andsr-100(resistant to 100 μg/ml of streptomycin). The wild-type phenotypes sensitive to these drugs have been designated asmss-500,ery-s-100andss-100respectively. Thesr-100also showed cross-resistance to other antibiotics belonging to the streptomycin group.On genetic analysis, themsr-500andery-s-100were found to be inherited in a Mendelian way. These alleles are not linked to each other or to the mating type locus. The inheritance of mating type was found to be due to a single gene difference.The inheritance ofss-100/sr-100was found to be non-chromosomal and was characteristically uniparental, always transmitted through the female parent. The evidence for the non-chromosomal gene (NC genes) controllingsr-100/ss-100phenotypes in this organism has been derived from the exceptional zygotes in which the male parent apparently transmits streptomycin resistance to the progeny. Although ultraviolet or gamma-radiation resulted in normal survival curves of the exposed cells, no mutant deficient in any nutritional requirement was isolated.

Sign in / Sign up

Export Citation Format

Share Document