scholarly journals Diversity of Mating-Type Chromosome Structures in the Yeast Zygosaccharomyces rouxii Caused by Ectopic Exchanges between MAT-Like Loci

PLoS ONE ◽  
2013 ◽  
Vol 8 (4) ◽  
pp. e62121 ◽  
Author(s):  
Jun Watanabe ◽  
Kenji Uehara ◽  
Yoshinobu Mogi
Keyword(s):  
Mating Type ◽  
Zygosaccharomyces Rouxii ◽  
Type Chromosome

scholarly journals Mechanism for Restoration of Fertility in Hybrid Zygosaccharomyces rouxii Generated by Interspecies Hybridization

2017 ◽  
Vol 83 (21) ◽  
Author(s):  
Jun Watanabe ◽  
Kenji Uehara ◽  
Yoshinobu Mogi ◽  
Yuichiro Tsukioka
Keyword(s):  
Mating Type ◽  
Whole Genome Duplication ◽  
Gene Loss ◽  
Genome Duplication ◽  
Draft Genome ◽  
Content Type ◽  
Zygosaccharomyces Rouxii ◽  
Interspecies Hybridization ◽  
Random Gene Loss ◽  
Interspecies Hybrid

ABSTRACT The mechanism of whole-genome duplication (WGD) in yeast has been intensively studied because it has a large impact on yeast evolution. WGD has shaped the genomic architecture of modern Saccharomyces cerevisiae; however, the mechanism for restoring fertility after interspecies hybridization, which would be involved in the process of WGD, has not been thoroughly elucidated. In this study, we obtained a draft genome sequence of the salt-tolerant yeast Zygosaccharomyces rouxii NBRC110957 and revealed that it is a hybrid lineage of Z. rouxii (allodiploid) with two subgenomes equivalent to NBRC1876. Because this allodiploid yeast can mate with other allodiploid strains and form spores, it can be a good model of restoring fertility after interspecies hybridization. We observed that NBRC110957 and NBRC1876 contain six mating-type-like (MTL) loci. There are no large deletions or deleterious mutations in MTL loci, except for several-base-pair deletions in the X region in certain MTL loci. We also assigned only one mating-type (MAT) locus that exclusively determines mating types from six MTL loci. These results suggest that it is possible to recover mating competence regardless of whether cells lose one MAT locus through random gene loss by mitotically dividing after interspecies hybridization. Moreover, we propose that perturbation of gene expression and substantial breakdown of MAT heterozygosity caused by chromosomal rearrangement at MTL loci play roles in restoring the mating competence of allodiploids. This scenario can provide a mechanism for restoring fertility after interspecies hybridization that is compatible with random gene loss models and suggests genomic plasticity during WGD in yeast. IMPORTANCE A whole-genome duplication occurred in an ancestor of the baker's yeast Saccharomyces cerevisiae. The origins of this complex and multifaceted process, which requires intra- or interspecies hybridization followed by dysfunction of one mating-type (MAT) locus to regain mating competence, has not been thoroughly elucidated. In this study, we provide a mechanism for regaining fertility in an interspecies hybrid, Zygosaccharomyces rouxii. The draft genome sequence analysis and mating test showed that the Z. rouxii strain used in this study is an intact interspecies hybrid, suggesting that it is possible to recover fertility regardless of whether cells lose one MAT locus.

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.

scholarly journals Interplay of Chimeric Mating-Type Loci Impairs Fertility Rescue and Accounts for Intra-Strain Variability in Zygosaccharomyces rouxii Interspecies Hybrid ATCC42981

2019 ◽  
Vol 10 ◽  
Author(s):  
Melissa Bizzarri ◽  
Stefano Cassanelli ◽  
Laura Bartolini ◽  
Leszek P. Pryszcz ◽  
Michala Dušková ◽  
...  
Keyword(s):  
Mating Type ◽  
Zygosaccharomyces Rouxii ◽  
Strain Variability ◽  
Interspecies Hybrid

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).

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