A possible inversion in the mating-type chromosome ofNeurospora crassa

Genetica ◽  
1959 ◽  
Vol 29 (1) ◽  
pp. 193-205 ◽  
Author(s):  
Osama M. Rifaat
Keyword(s):  
Mating Type ◽  
Ofneurospora Crassa ◽  
Type Chromosome

scholarly journals REGULATION OF MATING AND MEIOSIS IN YEAST BY THE MATING-TYPE REGION

Genetics ◽  
1976 ◽  
Vol 82 (2) ◽  
pp. 187-206
Author(s):  
Yona Kassir ◽  
Giora Simchen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Standard Laboratory ◽  
Tetrad Analysis ◽  
Type Region ◽  
Type Locus ◽  
Dominance Relations ◽  
Yeast Strains ◽  
Additional Locus ◽  
Type Chromosome

ABSTRACT A supposed sporulation-deficient mutation of Saccharomyces cerevisiae is found to affect mating in haploids and in diploids, and to be inseparable from the mating-type locus by recombination. The mutation is regarded as a defective a allele and is designated a*. This is confirmed by its dominance relations in diploids, triploids, and tetraploids. Tetrad analysis of tetraploids and of their sporulating diploid progeny suggests the existence of an additional locus, RME, which regulates sporulation in yeast strains that can mate. Thus the recessive homozygous constitution rme/rme enables the diploids a*/α, a/a*, and α/α to go through meiosis. Haploids carrying rme show apparent premeiotic DNA replication in sporulation conditions. This new regulatory locus is linked to the centromere of the mating-type chromosome, and its two alleles, rme and RME, are found among standard laboratory strains.

scholarly journals Genetic recombination in Neurospora crassa and N. sitophila

1965 ◽  
Vol 6 (2) ◽  
pp. 216-225 ◽  
Author(s):  
M. B. Scott-Emuakpor
Keyword(s):  
Linkage Group ◽  
Neurospora Crassa ◽  
Mating Type ◽  
Genetic Recombination ◽  
Evolutionary Significance ◽  
Linkage Groups ◽  
Group Vi ◽  
Group I ◽  
Mutant Genes ◽  
Type Chromosome

Mutant genes in linkage groups I (mating-type chromosome), VI and VII have been transferred from Neurospora crassa to N. sitophila by hybridization and repeated backcrossing. Recombination between these genes has been studied from five-point crosses involving linkage group I and three-point crosses involving linkage groups VI and VII of the two species.The results show significant differences in the amount of recombination between some of the genes in the proximal regions of the mating-type chromosomes of the two species. They indicate proximal localization of crossovers in the mating-type chromosome of N. sitophila. The results also show significant differences in recombination frequency between the genes in linkage group VI and a close similarity in linkage group VII. They further show that the centromere in the two species may not be interfering with crossing-over in its vicinity to such an extent as to be of any evolutionary significance.

scholarly journals Pseudohomothallism and Evolution of the Mating-Type Chromosome in Neurospora tetrasperma

Genetics ◽  
1996 ◽  
Vol 143 (2) ◽  
pp. 789-799 ◽  
Author(s):  
Sandra T Merino ◽  
Mary Anne Nelson ◽  
David J Jacobson ◽  
Donald O Natvig
Keyword(s):  
Genetic Variability ◽  
Mating Type ◽  
High Frequency ◽  
Population Biology ◽  
Unexpected Result ◽  
Evolutionary Time ◽  
Distinct Haplotype ◽  
Suppressed Recombination ◽  
Neurospora Tetrasperma ◽  
Type Chromosome

Abstract Ascospores of Neurospora tetrasperma normally contain nuclei of both mating-type idiomorphs (a and A), resulting in self-fertile heterokaryons (a type of sexual reproduction termed pseudohomothallism). Occasional homokaryotic self-sterile strains (either a or A) behave as heterothallics and, in principle, provide N. tetrasperma with a means for facultative outcrossing. This studywas conceived as an investigation of the population biology of N. tetrasperma to assess levels of intrastrain heterokaryosis (heterozygosity). The unexpected result was that the mating-type chromosome and autosomes exhibited very different patterns of evolution, apparently because of suppressed recombination between mating-type chromosomes. Analysis of sequences on the mating-type chromosomes of wild-collected self-fertile strains revealed high levels of genetic variability between sibling A and a nuclei. In contrast, sequences on autosomes of sibling A and a nuclei exhibited nearly complete homogeneity. Conservation of distinct haplotype combinations on A and a mating-type chromosomes in strains from diverse locations further suggested an absence of recombination over substantial periods of evolutionary time. The suppression of recombination on the N. tetrasperma mating-type chromosome, expected to ensure a high frequency of self fertility, presents an interesting parallel with, and possible model for studying aspects of, the evolution of mammalian sex chromosomes.

The mating-type locus ofNeurospora crassa

1996 ◽  
Vol 75 (3) ◽  
pp. 341-350 ◽  
Author(s):  
Chuck Staben
Keyword(s):  
Mating Type ◽  
Type Locus ◽  
Mating Type Locus ◽  
Ofneurospora Crassa

scholarly journals Interference studies in Neurospora crassa and N. sitophila

1965 ◽  
Vol 6 (2) ◽  
pp. 226-229 ◽  
Author(s):  
M. B. Scott-Emuakpor
Keyword(s):  
Linkage Group ◽  
Neurospora Crassa ◽  
Mating Type ◽  
Marker Genes ◽  
Linkage Groups ◽  
Group I ◽  
Interference Studies ◽  
Type Chromosome ◽  
Chiasma Interference

Tetrad data from five-point crosses involving linkage group I (mating-type chromosome) and three-point crosses involving linkage groups VI and VII of Neurospora crassa and N. sitophila have been analysed in order to detect the phenomena of chromatid and chiasma interference on a comparative basis. Marker genes were transferred from N. crassa to N. sitophila by hybridization and repeated back crossing. The details of the methods of transfer and of making crosses have been described in a previous paper (Scott-Emuakpor, 1965).

scholarly journals Suppressed Recombination and a Pairing Anomaly on the Mating-Type Chromosome of Neurospora tetrasperma

Genetics ◽  
2000 ◽  
Vol 154 (2) ◽  
pp. 623-633 ◽  
Author(s):  
Alena Gallegos ◽  
David J Jacobson ◽  
Namboori B Raju ◽  
Marian P Skupski ◽  
Donald O Natvig
Keyword(s):  
Mating Type ◽  
Mitotic Division ◽  
Crossing Over ◽  
Unpaired Region ◽  
Wild Strains ◽  
Suppressed Recombination ◽  
Pseudoautosomal Regions ◽  
Neurospora Tetrasperma ◽  
Type Chromosome ◽  
Chromosome Disjunction

Abstract Neurospora crassa and related heterothallic ascomycetes produce eight homokaryotic self-sterile ascospores per ascus. In contrast, asci of N. tetrasperma contain four self-fertile ascospores each with nuclei of both mating types (matA and mata). The self-fertile ascospores of N. tetrasperma result from first-division segregation of mating type and nuclear spindle overlap at the second meiotic division and at a subsequent mitotic division. Recently, Merino et al. presented population-genetic evidence that crossing over is suppressed on the mating-type chromosome of N. tetrasperma, thereby preventing second-division segregation of mating type and the formation of self-sterile ascospores. The present study experimentally confirmed suppressed crossing over for a large segment of the mating-type chromosome by examining segregation of markers in crosses of wild strains. Surprisingly, our study also revealed a region on the far left arm where recombination is obligatory. In cytological studies, we demonstrated that suppressed recombination correlates with an extensive unpaired region at pachytene. Taken together, these results suggest an unpaired region adjacent to one or more paired regions, analogous to the nonpairing and pseudoautosomal regions of animal sex chromosomes. The observed pairing and obligate crossover likely reflect mechanisms to ensure chromosome disjunction.

Development of a PCR assay for amplification of mating-type loci of Alternaria spp. and related fungi.

2013 ◽  
Vol 65 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Philipp B. Gannibal ◽  
Igor A. Kazartsev
Keyword(s):  
Mating Type ◽  
Pcr Assay
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