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 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 Deletion of the Schizophyllum commune Aα Locus: The Roles of Aα Y and Z Mating-Type Genes

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1437-1444
Author(s):  
C Ian Robertson ◽  
Kirk A Bartholomew ◽  
Charles P Novotny ◽  
Robert C Ullrich
Keyword(s):  
Mating Type ◽  
Sexual Development ◽  
Schizophyllum Commune ◽  
Mating Types ◽  
Developmental Pathway ◽  
Mating Type Gene ◽  
Mating Type Genes ◽  
Regulatory Loci ◽  
Type Gene

The Aα locus is one of four master regulatory loci that determine mating type and regulate sexual development in Schizophyllum commune. We have made a plasmid containing a URA1 gene disruption of the Aα Y1 gene. Y1 is the sole Aα gene in Aα1 strains. We used the plasmid construction to produce an Aα null (i.e., AαΔ) strain by replacing the genomic Y1 gene with URA1 in an Aα1 strain. To characterize the role of the Aα genes in the regulation of sexual development, we transformed various Aα Y and Z alleles into AαΔ strains and examined the acquired mating types and mating abilities of the transformants. These experiments demonstrate that the Aα Y gene is not essential for fungal viability and growth, that a solitary Z Aα mating-type gene does not itself activate development, that Aβ proteins are sufficient to activate the A developmental pathway in the absence of Aα proteins and confirm that Y and Z genes are the sole determinants of Aα mating type. The data from these experiments support and refine our model of the regulation of A-pathway events by Y and Z proteins.

scholarly journals Genomic and Population Analyses of the Mating Type Loci in Coccidioides Species Reveal Evidence for Sexual Reproduction and Gene Acquisition

2007 ◽  
Vol 6 (7) ◽  
pp. 1189-1199 ◽  
Author(s):  
M. Alejandra Mandel ◽  
Bridget M. Barker ◽  
Scott Kroken ◽  
Steven D. Rounsley ◽  
Marc J. Orbach
Keyword(s):  
Sexual Reproduction ◽  
Mating Type ◽  
Mating Types ◽  
Coccidioides Immitis ◽  
Genome Sequences ◽  
Valley Fever ◽  
Population Analyses ◽  
Gene Acquisition ◽  
Close Proximity

ABSTRACT Coccidioides species, the fungi responsible for the valley fever disease, are known to reproduce asexually through the production of arthroconidia that are the infectious propagules. The possible role of sexual reproduction in the survival and dispersal of these pathogens is unexplored. To determine the potential for mating of Coccidioides, we analyzed genome sequences and identified mating type loci characteristic of heterothallic ascomycetes. Coccidioides strains contain either a MAT1-1 or a MAT1-2 idiomorph, which is 8.1 or 9 kb in length, respectively, the longest reported for any ascomycete species. These idiomorphs contain four or five genes, respectively, more than are present in the MAT loci of most ascomycetes. Along with their cDNA structures, we determined that all genes in the MAT loci are transcribed. Two genes frequently found in common sequences flanking MAT idiomorphs, APN2 and COX13, are within the MAT loci in Coccidioides, but the MAT1-1 and MAT1-2 copies have diverged dramatically from each other. Data indicate that the acquisition of these genes in the MAT loci occurred prior to the separation of Coccidioides from Uncinocarpus reesii. An analysis of 436 Coccidioides isolates from patients and the environment indicates that in both Coccidioides immitis and C. posadasii, there is a 1:1 distribution of MAT loci, as would be expected for sexually reproducing species. In addition, an analysis of isolates obtained from 11 soil samples demonstrated that at three sampling sites, strains of both mating types were present, indicating that compatible strains were in close proximity in the environment.

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.

scholarly journals Mating-Type Gene Structure and Spatial Distribution of Didymella tanaceti in Pyrethrum Fields

2016 ◽  
Vol 106 (12) ◽  
pp. 1521-1529 ◽  
Author(s):  
Tamieka L. Pearce ◽  
Jason B. Scott ◽  
Frank S. Hay ◽  
Sarah J. Pethybridge
Keyword(s):  
Spatial Distribution ◽  
Mating Type ◽  
Tan Spot ◽  
Mating Types ◽  
Tanacetum Cinerariifolium ◽  
Polymerase Chain ◽  
Type Gene ◽  
Mat Genes

Tan spot of pyrethrum (Tanacetum cinerariifolium) is caused by the ascomycete Didymella tanaceti. To assess the evolutionary role of ascospores in the assumed asexual species, the structure and arrangement of mating-type (MAT) genes were examined. A single MAT1-1 or MAT1-2 idiomorph was identified in all isolates examined, indicating that the species is heterothallic. The idiomorphs were flanked upstream and downstream by regions encoding pyridoxamine phosphate oxidase-like and DNA lyase-like proteins, respectively. A multiplex MAT-specific polymerase chain reaction assay was developed and used to genotype 325 isolates collected within two transects in each of four fields in Tasmania, Australia. The ratio of isolates of each mating-type in each transect was consistent with a 1:1 ratio. The spatial distribution of the isolates of the two mating-types within each transect was random for all except one transect for MAT1-1 isolates, indicating that clonal patterns of each mating-type were absent. However, evidence of a reduced selection pressure on MAT1-1 isolates was observed, with a second haplotype of the MAT1-1-1 gene identified in 4.4% of MAT1-1 isolates. In vitro crosses between isolates with opposite mating-types failed to produce ascospores. Although the sexual morph could not be induced, the occurrence of both mating-types in equal frequencies suggested that a cryptic sexual mode of reproduction may occur within field populations.

A STUDY OF ODD MATING-TYPE DETERMINATION FACTOR BY TRANSFER OF MACRONUCLEAR KARYOPLASM IN PARAMECIUM TETRAURELIA

Genetics ◽  
1984 ◽  
Vol 107 (3) ◽  
pp. 367-373
Author(s):  
Sadaaki Koizumi ◽  
Sumiko Kobayashi
Keyword(s):  
Mating Type ◽  
Direct Evidence ◽  
Unique Feature ◽  
Sensitive Period ◽  
Paramecium Tetraurelia ◽  
Sexual Stage ◽  
Determining Factors ◽  
Determining Factor

ABSTRACT The unique feature of the "B system" of mating-type determination found in Paramecium tetraurelia is the existence of a cytoplasmic difference between odd (O) and even (E) cells created and maintained by the action of their macronuclei. Thus far, the presence of a determining factor that controls the differentiation of the developing zygotic macronucleus for O mating type has not been verified. Results of crosses between cells of differing clonal age and complementary mating type suggest that, for one to two fissions after autogamy, O cells produce some factor that determines the gametic nucleus (micronucleus) as mating type O. Direct evidence for the production of O-determining factor by the young O macronucleus was obtained by transplanting young O macronuclear karyoplasm (a part of the macronucleus) into E cells: 32-35% of E exautogamous clones transformed to O; transformation of E exautogamous clones to O reached as high as 72% by transfer of young O macronuclear karyoplasm from a conjugant, 3-4 hr after mixing. This indicates that O determinants produced by the O macronucleus can also act during the sensitive period of development of the new macronucleus. These O-determining factors may be produced or activated at the sexual stage and then decrease in activity in subsequent fissions after new macronuclear reorganization.

scholarly journals Evolution of asymmetric gamete signaling and suppressed recombination at the mating type locus

2019 ◽  
Author(s):  
Zena Hadjivasiliou ◽  
Andrew Pomiankowski
Keyword(s):  
Mating Type ◽  
Mating Types ◽  
Linkage Groups ◽  
Type Locus ◽  
The Road ◽  
Receptor Dynamics ◽  
Tight Linkage ◽  
Suppressed Recombination ◽  
Selection For

AbstractThe two partners required for sexual reproduction are rarely the same. This pattern extends to species which lack sexual dimorphism yet possess self-incompatible gametes determined at mating-type regions of suppressed recombination, likely precursors of sex chromosomes. Here we investigate the role of cellular signaling in the evolution of mating-types. We develop a model of ligand-receptor dynamics within cells, and identify factors that determine the capacity of cells to send and receive signals. The model specifies conditions favoring the evolution of gametes producing ligand and receptor asymmetrically and shows how these are affected by recombination. When the recombination rate can evolve, the conditions favoring asymmetric signaling also favor tight linkage of ligand and receptor loci in distinct linkage groups. These results suggest that selection for asymmetric signaling between gametes was the first step in the evolution of non-recombinant mating-type loci, paving the road for the evolution of anisogamy and sexes.

scholarly journals Evolution of asymmetric gamete signaling and suppressed recombination at the mating type locus

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Zena Hadjivasiliou ◽  
Andrew Pomiankowski
Keyword(s):  
Mating Type ◽  
Mating Types ◽  
Linkage Groups ◽  
Type Locus ◽  
The Road ◽  
Receptor Dynamics ◽  
Tight Linkage ◽  
Suppressed Recombination ◽  
Selection For

The two partners required for sexual reproduction are rarely the same. This pattern extends to species which lack sexual dimorphism yet possess self-incompatible gametes determined at mating-type regions of suppressed recombination, likely precursors of sex chromosomes. Here we investigate the role of cellular signaling in the evolution of mating-types. We develop a model of ligand-receptor dynamics, and identify factors that determine the capacity of cells to send and receive signals. The model specifies conditions favoring the evolution of gametes producing ligand and receptor asymmetrically and shows how these are affected by recombination. When the recombination rate evolves, the conditions favoring asymmetric signaling also favor tight linkage of ligand and receptor loci in distinct linkage groups. These results suggest that selection for asymmetric gamete signaling could be the first step in the evolution of non-recombinant mating-type loci, paving the road for the evolution of anisogamy and sexes.

General Particulars Regarding the Conflict of Interest

2020 ◽  
Vol 26 (2) ◽  
pp. 145-149
Author(s):  
Aurelia Teodora Drăghici
Keyword(s):  
Local Government ◽  
Conflict Of Interest ◽  
Conflicts Of Interest ◽  
National Level ◽  
The State ◽  
Role Of The State ◽  
Legal Implications ◽  
Determining Factors ◽  
Changing Role

SummaryTheme conflicts of interest is one of the major reasons for concern local government, regional and central administrative and criminal legal implications aiming to uphold the integrity and decisions objectively. Also, most obviously, conflicts of interest occur at the national level where political stakes are usually highest, one of the determining factors of this segment being the changing role of the state itself, which creates opportunities for individual gain through its transformations.

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