scholarly journals TETRAPLOID STRAINS OF SACCHAROMYCES CEREVISIAE THAT ARE TRISOMIC FOR CHROMOSOME III

Genetics ◽  
1978 ◽  
Vol 89 (4) ◽  
pp. 667-684
Author(s):  
Michael I Riley ◽  
T R Manney
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Computer Simulation ◽  
Meiotic Recombination ◽  
Meiotic Segregation ◽  
Segregation Data ◽  
Strong Interference ◽  
Chromosome Iii ◽  
Double Crossovers

ABSTRACT Meiotic segregation of several genes has been studied in tetraploid strains that are trisomic for chromosome III. The segregation data were compared to a computer simulation that assumes trivalent pairing of homologues involved in exchanges, followed by nonpreferential segregation. Trivalent pairing was characterized by higher frequencies of exchange as compared to bivalent pairing, and by the presence of spores resulting from at least double crossovers involving all three homologues. Trivalent segregation was characterized by a unique recombinant class. The strong interference normally exhibited in diploid meiotic recombination was not evident from the frequency of double crossovers in these strains.

scholarly journals Identification of new genes required for meiotic recombination in Saccharomyces cerevisiae.

Genetics ◽  
1993 ◽  
Vol 133 (1) ◽  
pp. 51-66 ◽  
Author(s):  
M Ajimura ◽  
S H Leem ◽  
H Ogawa
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Specific Gene ◽  
Early Step ◽  
Haploid Strain ◽  
New Genes ◽  
Intragenic Complementation ◽  
Complementation Groups ◽  
Chromosome Iii ◽  
Unusual Phenotype

Abstract Mutants defective in meiotic recombination were isolated from a disomic haploid strain of Saccharomyces cerevisiae by examining recombination within the leu2 and his4 heteroalleles located on chromosome III. The mutants were classified into two new complementation groups (MRE2 and MRE11) and eight previously identified groups, which include SPO11, HOP1, REC114, MRE4/MEK1 and genes in the RAD52 epistasis group. All of the mutants, in which the mutations in the new complementation groups are homozygous and diploid, can undergo premeiotic DNA synthesis and produce spores. The spores are, however, not viable. The mre2 and mre11 mutants produce viable spores in a spo13 background, in which meiosis I is bypassed, suggesting that these mutants are blocked at an early step in meiotic recombination. The mre2 mutant does not exhibit any unusual phenotype during mitosis and it is, thus, considered to have a mutation in a meiosis-specific gene. By contrast, the mre11 mutant is sensitive to damage to DNA by methyl methanesulfonate and exhibits a hyperrecombination phenotype in mitosis. Among six alleles of HOP1 that were isolated, an unusual pattern of intragenic complementation was observed.

scholarly journals Stimulation of meiotic recombination in yeast by an ARS element.

Genetics ◽  
1993 ◽  
Vol 134 (1) ◽  
pp. 175-188
Author(s):  
A J Rattray ◽  
L S Symington
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Meiotic Recombination ◽  
Replication Origin ◽  
Chromosome Iii ◽  
Gene Conversions ◽  
Stimulation Of

Abstract In a previous study, meiotic recombination events were monitored in the 22-kb LEU2 to CEN3 region of chromosome III of Saccharomyces cerevisiae. One region (the hotspot) was shown to have an enhanced level of both gene conversion events and reciprocal crossovers, whereas a second region (the coldspot) was shown to have a depressed level of both types of recombination events. In this study we have analyzed the effects of a replication origin, ARS307, located about 2 kb centromere proximal to the hotspot region, on the distribution of meiotic recombination events. We find that a deletion of this origin results in a reduction of both gene conversions and reciprocal crossovers in the hotspot region, and that a 200-bp fragment of this ARS element can stimulate both types of recombination events when relocated to the coldspot region. Although the magnitude of stimulation of these events is similar in both orientations, whether the ARS is functional or not, the distribution of events is dependent upon the orientation of the element.

scholarly journals A polymerization model of chiasma interference and corresponding computer simulation.

Genetics ◽  
1990 ◽  
Vol 126 (4) ◽  
pp. 1127-1138 ◽  
Author(s):  
J S King ◽  
R K Mortimer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Computer Simulation ◽  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Meiotic Recombination ◽  
Polymerization Reaction ◽  
Proposed Model ◽  
Random Events ◽  
Chromosome Arm ◽  
Chiasma Interference

Abstract A model of chiasma interference is proposed and simulated on a computer. The model uses random events and a polymerization reaction to regulate meiotic recombination between and along chromosomes. A computer simulation of the model generates distributions of crossovers per chromosome arm, position of events along the chromosome arm, distance between crossovers in two-event tetrads, and coincidence as a function of distance. Outputs from the simulation are compared to data from Saccharomyces cerevisiae and the X chromosome of Drosophila melanogaster. The simulation demonstrates that the proposed model can produce the regulation of recombination observed in both genetic and cytological experiments. While the model was quantitatively compared to data from only Drosophila and Saccharomyces, the regulation observed in these species is qualitatively similar to the regulation of recombination observed in other organisms.

scholarly journals Distributive disjunction of authentic chromosomes in Saccharomyces cerevisiae.

Genetics ◽  
1991 ◽  
Vol 127 (3) ◽  
pp. 475-488 ◽  
Author(s):  
V Guacci ◽  
D B Kaback
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Drosophila Melanogaster ◽  
Full Length ◽  
Chromosome Size ◽  
Meiotic Segregation ◽  
Yeast Saccharomyces Cerevisiae ◽  
Homologous Chromosomes ◽  
Chromosome Fragments ◽  
Chromosome Iii ◽  
Chromosome I

Abstract Distributive disjunction is defined as the first division meiotic segregation of either nonhomologous chromosomes that lack homologs or homologous chromosomes that have not recombined. To determine if chromosomes from the yeast Saccharomyces cerevisiae were capable of distributive disjunction, we constructed a strain that was monosomic for both chromosome I and chromosome III and analyzed the meiotic segregation of the two monosomic chromosomes. In addition, we bisected chromosome I into two functional chromosome fragments, constructed strains that were monosomic for both chromosome fragments and examined meiotic segregation of the chromosome fragments in the monosomic strains. The two nonhomologous chromosomes or chromosome fragments appeared to segregate from each other in approximately 90% of the asci analyzed, indicating that yeast chromosomes were capable of distributive disjunction. We also examined the ability of a small nonhomologous centromere containing plasmid to participate in distributive disjunction with the two nonhomologous monosomic chromosomes. The plasmid appeared to efficiently participate with the two full length chromosomes suggesting that distributive disjunction in yeast is not dependent on chromosome size. Thus, distributive disjunction in S. cerevisiae appears to be different from Drosophila melanogaster where a different sized chromosome is excluded from distributive disjunction when two similar size nonhomologous chromosomes are present.

scholarly journals Genetic analysis of a meiotic recombination hotspot on chromosome III of Saccharomyces cerevisiae.

Genetics ◽  
1991 ◽  
Vol 128 (4) ◽  
pp. 717-727 ◽  
Author(s):  
L S Symington ◽  
A Brown ◽  
S G Oliver ◽  
P Greenwell ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Genetic Analysis ◽  
Gene Conversion ◽  
Meiotic Recombination ◽  
Initiation Site ◽  
Recombination Hotspot ◽  
Chromosome Iii

Abstract In a previous study, we analyzed meiotic recombination events that occurred in the 22-kb region (LEU2 to CEN3) of chromosome III of Saccharomyces cerevisiae. We found one region with an enhanced level of crossovers (a hotspot) and one region with a depressed level of crossovers. In this study, we show that about one-third of the crossovers that occur between LEU2 and CEN3 are initiated in a 1.3-kb region located approximately 6 kb from the centromere. Both crossovers and gene conversion events are initiated at this site. Events initiated at this position can be resolved as crossovers in regions located either centromere-distally or centromere-proximally from the initiation site.

scholarly journals Poorly Repaired Mismatches in Heteroduplex DNA are Hyper-Recombinagenic in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 407-416 ◽  
Author(s):  
P Manivasakam ◽  
Susan M Rosenberg ◽  
P J Hastings
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mismatch Repair ◽  
Genetic Markers ◽  
Meiotic Recombination ◽  
Repair System ◽  
Normal Allele ◽  
Heteroduplex Dna ◽  
Mismatch Repair System ◽  
Postmeiotic Segregation ◽  
System Operating

Abstract In yeast meiotic recombination, alleles used as genetic markers fall into two classes as regards their fate when incorporated into heteroduplex DNA. Normal alleles are those that form heteroduplexes that are nearly always recognized and corrected by the mismatch repair system operating in meiosis. High PMS (postmeiotic segregation) alleles form heteroduplexes that are inefficiently mismatch repaired. We report that placing any of several high PMS alleles very close to normal alleles causes hyperrecombination between these markers. We propose that this hyperrecombination is caused by the high PMS allele blocking a mismatch repair tract initiated from the normal allele, thus preventing corepair of the two alleles, which would prevent formation of recombinants. The results of three point crosses involving two PMS alleles and a normal allele suggest that high PMS alleles placed between two alleles that are normally corepaired block that corepair.

scholarly journals Nonrecombinant meiosis I nondisjunction in Saccharomyces cerevisiae induced by tRNA ochre suppressors.

Genetics ◽  
1989 ◽  
Vol 123 (1) ◽  
pp. 81-95 ◽  
Author(s):  
E J Louis ◽  
J E Haber
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitotic Chromosome ◽  
Stop Codon ◽  
Fold Increase ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Nonsense Mutations ◽  
Chromosome Iii ◽  
Meiosis I ◽  
Chromosome Nondisjunction

Abstract The presence of the tRNA ochre suppressors SUP11 and SUP5 is found to induce meiosis I nondisjunction in the yeast Saccharomyces cerevisiae. The induction increases with increasing dosage of the suppressor and decreases in the presence of an antisuppressor. The effect is independent of the chromosomal location of SUP11. Each of five different chromosomes monitored exhibited nondisjunction at frequencies of 0.1%-1.1% of random spores, which is a 16-160-fold increase over wild-type levels. Increased nondisjunction is reflected by a marked increase in tetrads with two and zero viable spores. In the case of chromosome III, for which a 50-cM map interval was monitored, the resulting disomes are all in the parental nonrecombinant configuration. Recombination along chromosome III appears normal both in meioses that have no nondisjunction and in meioses for which there was nondisjunction of another chromosome. We propose that a proportion of one or more proteins involved in chromosome pairing, recombination or segregation are aberrant due to translational read-through of the normal ochre stop codon. Hygromycin B, an antibiotic that can suppress nonsense mutations via translational read-through, also induces nonrecombinant meiosis I nondisjunction. Increases in mistranslation, therefore, increase the production of aneuploids during meiosis. There was no observable effect of SUP11 on mitotic chromosome nondisjunction; however some disomes caused SUP11 ade2-ochre strains to appear white or red, instead of pink.

scholarly journals Crossover Interference in Saccharomyces cerevisiae Requires a TID1/RDH54- and DMC1-Dependent Pathway

Genetics ◽  
2003 ◽  
Vol 163 (4) ◽  
pp. 1273-1286 ◽  
Author(s):  
Miki Shinohara ◽  
Kazuko Sakai ◽  
Akira Shinohara ◽  
Douglas K Bishop
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Strand Break ◽  
Tetrad Analysis ◽  
Yeast Saccharomyces Cerevisiae ◽  
Crossover Interference ◽  
Meiotic Progression ◽  
Invasion Stage ◽  
Strand Invasion ◽  
Dependent Pathway

Abstract Two RecA-like recombinases, Rad51 and Dmc1, function together during double-strand break (DSB)-mediated meiotic recombination to promote homologous strand invasion in the budding yeast Saccharomyces cerevisiae. Two partially redundant proteins, Rad54 and Tid1/Rdh54, act as recombinase accessory factors. Here, tetrad analysis shows that mutants lacking Tid1 form four-viable-spore tetrads with levels of interhomolog crossover (CO) and noncrossover recombination similar to, or slightly greater than, those in wild type. Importantly, tid1 mutants show a marked defect in crossover interference, a mechanism that distributes crossover events nonrandomly along chromosomes during meiosis. Previous work showed that dmc1Δ mutants are strongly defective in strand invasion and meiotic progression and that these defects can be partially suppressed by increasing the copy number of RAD54. Tetrad analysis is used to show that meiotic recombination in RAD54-suppressed dmc1Δ cells is similar to that in tid1; the frequency of COs and gene conversions is near normal, but crossover interference is defective. These results support the proposal that crossover interference acts at the strand invasion stage of recombination.

Linkage group XIX of Chlamydomonas reinhardtii has a linear map.

Genetics ◽  
1993 ◽  
Vol 133 (4) ◽  
pp. 865-874
Author(s):  
J A Holmes ◽  
D E Johnson ◽  
S K Dutcher
Keyword(s):  
Linkage Group ◽  
Chlamydomonas Reinhardtii ◽  
Mutant Strain ◽  
Meiotic Recombination ◽  
Temperature Sensitive ◽  
Unusual Property ◽  
Linkage Groups ◽  
Excess Number ◽  
Chiasma Interference ◽  
Double Crossovers

Abstract Linkage group XIX (or the UNI linkage group) of Chlamydomonas reinhardtii has been reported to show a circular meiotic recombination map. A circular map predicts the existence of strong chiasma and chromatid interference, which would lead to an excess number of two-strand double crossovers during meiosis. We have tested this prediction in multipoint crosses. Our results are consistent with a linear linkage group that shows positive chiasma interference and no chromatid interference. Chiasma interference occurs both within arms and across the centromere. Of the original loci that contributed to the circular map, we find that two map to other linkage groups and a third cannot be retested because the mutant strain that defined it has been lost. A second reported unusual property for linkage group XIX was the increase in meiotic recombination with increases in temperature during a period that precedes the onset of meiosis. Although we observed changes in recombination frequencies in some intervals on linkage group XIX in crosses to CC-1952, and in strains heterozygous for the mutation ger1 at 16 degrees, we also show that our strains do not exhibit the previously observed patterns of temperature-sensitive recombination for two different pairs of loci on linkage group XIX. We conclude that linkage group XIX has a linear genetic map that is not significantly different from other Chlamydomonas linkage groups.

scholarly journals Suppressor Analysis of the Saccharomyces cerevisiae Gene REC104 Reveals a Genetic Interaction With REC102

Genetics ◽  
1999 ◽  
Vol 151 (4) ◽  
pp. 1261-1272 ◽  
Author(s):  
Laura Salem ◽  
Natalie Walter ◽  
Robert Malone
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Null Allele ◽  
Genetic Interaction ◽  
In Vitro Mutagenesis ◽  
Conditional Mutations ◽  
Suppressor Analysis

Abstract REC104 is a gene required for the initiation of meiotic recombination in Saccharomyces cerevisiae. To better understand the role of REC104 in meiosis, we used an in vitro mutagenesis technique to create a set of temperature-conditional mutations in REC104 and used one ts allele (rec104-8) in a screen for highcopy suppressors. An increased dosage of the early exchange gene REC102 was found to suppress the conditional recombinational reduction in rec104-8 as well as in several other conditional rec104 alleles. However, no suppression was observed for a null allele of REC104, indicating that the suppression by REC102 is not “bypass” suppression. Overexpression of the early meiotic genes REC114, RAD50, HOP1, and RED1 fails to suppress any of the rec104 conditional alleles, indicating that the suppression might be specific to REC102.

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