Meiotic Crossing Over Between Nonhomologous Chromosomes Affects Chromosome Segregation in Yeast

Genetics ◽  
1997 ◽  
Vol 146 (1) ◽  
pp. 69-78
Author(s):  
Sue Jinks-Robertson ◽  
Shariq Sayeed ◽  
Tamara Murphy
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Chromosome Segregation ◽  
Meiotic Recombination ◽  
Southern Blot Analysis ◽  
Meiotic Chromosome ◽  
Crossing Over ◽  
Yeast Saccharomyces Cerevisiae ◽  
Reciprocal Translocations ◽  
Ectopic Recombination

Meiotic recombination between artificial repeats positioned on nonhomologous chromosomes occurs efficiently in the yeast Saccharomyces cerevisiae. Both gene conversion and crossover eventS have been observed, with crossovers yielding reciprocal translocations. In the current study, 5.5-kb ura3 repeats positioned on chromosomes V and XV were used to examine the effect of ectopic recombination on meiotic chromosome segregation. Ura+ random spores were selected and gene conversion vs. crossover events were distinguished by Southern blot analysis. Approximately 15% of the crossover events between chromosomes V and XV were associated with missegregation of one of these chromosomes. The missegregation was manifest as hyperploid spores containing either both translocations plus a normal chromosome, or both normal chromosomes plus one of the translocations. In those cases where it could be analyzed, missegregation occurred at the first meiotic division. These data are discussed in terms of a model in which ectopic crossovers compete efficiently with normal allelic crossovers in directing meiotic chromosome segregation.

scholarly journals Gene conversions and crossing over during homologous and homeologous ectopic recombination in Saccharomyces cerevisiae.

Genetics ◽  
1993 ◽  
Vol 135 (1) ◽  
pp. 5-16 ◽  
Author(s):  
S Harris ◽  
K S Rudnicki ◽  
J E Haber
Keyword(s):  
Gene Conversion ◽  
Low Ph ◽  
Ammonium Ion ◽  
Crossing Over ◽  
Hygromycin B ◽  
Wild Type ◽  
Reciprocal Translocations ◽  
Ectopic Recombination ◽  
Shared Identity ◽  
The Difference

Abstract The pma1-105 mutation reduces the activity of the yeast plasma membrane H(+)-ATPase and causes cells to be both low pH and ammonium ion sensitive and resistant to the antibiotic hygromycin B. Revertants that can grow at pH 3.0 and on ammonium-containing plates frequently arise by ectopic recombination between pma1-105 and PMA2, a diverged gene that shares 85% DNA sequence identity with PMA1. The gene conversion tracts of revertants of pma1-105 were determined by DNA sequencing the hybrid PMA1::PMA2 genes. Gene conversion tracts ranged from 18-774 bp. The boundaries of these replacements were short (3-26 bp) regions of sequences that were identical between PMA1 and PMA2. These boundaries were not located at the regions of greatest shared identity between the two PMA genes. Similar results were obtained among low pH-resistant revertants of another mutation, pma1-147. One gene conversion was obtained in which the resulting PMA1::PMA2 hybrid was low pH-resistant but still hygromycin B-resistant. This partially active gene differs from a wild-type revertant only by the presence of two PMA2-encoded amino acid substitutions. Thus, some regions of PMA2 are not fully interchangeable with PMA1. We have also compared the efficiency of recombination between pma1-105 and either homeologous PMA2 sequence or homologous PMA1 donor sequences inserted at the same location. PMA2 x pma1-105 recombination occurred at a rate approximately 75-fold less than PMA1 x pma1-105 events. The difference in homology between the interacting sequences did not affect the proportion of gene conversion events associated with a cross-over, as in both cases approximately 5% of the Pma+ recombinants had undergone reciprocal translocations between the two chromosomes carrying pma1-105 and the donor PMA sequences. Reciprocal translocations were identified by a simple and generally useful nutritional test.

scholarly journals SSP1, a gene necessary for proper completion of meiotic divisions and spore formation in Saccharomyces cerevisiae.

1997 ◽  
Vol 17 (12) ◽  
pp. 7029-7039 ◽  
Author(s):  
D K Nag ◽  
M P Koonce ◽  
J Axelrod
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Chromosome Segregation ◽  
Meiotic Recombination ◽  
Nuclear Division ◽  
Diploid Cell ◽  
Spore Formation ◽  
Yeast Saccharomyces Cerevisiae ◽  
Expression Of Genes ◽  
Diploid Cells ◽  
Differential Expression Of Genes

During meiosis, a diploid cell undergoes two rounds of nuclear division following one round of DNA replication to produce four haploid gametes. In yeast, haploid meiotic products are packaged into spores. To gain new insights into meiotic development and spore formation, we followed differential expression of genes in meiotic versus vegetatively growing cells in the yeast Saccharomyces cerevisiae. Our results indicate that there are at least five different classes of transcripts representing genes expressed at different stages of the sporulation program. Here we describe one of these differentially expressed genes, SSP1, which plays an essential role in meiosis and spore formation. SSP1 is expressed midway through meiosis, and homozygous ssp1 diploid cells fail to sporulate. In the ssp1 mutant, meiotic recombination is normal but viability declines rapidly. Both meiotic divisions occur at the normal time; however, the fraction of cells completing meiosis is significantly reduced, and nuclei become fragmented soon after meiosis II. The ssp1 defect does not appear to be related to a microtubule-cytoskeletal-dependent event and is independent of two rounds of chromosome segregation. The data suggest that Ssp1 is likely to function in a pathway that controls meiotic nuclear divisions and coordinates meiosis and spore formation.

scholarly journals MAPPING AND GENE CONVERSION STUDIES WITH THE STRUCTURAL GENE FOR ISO-1-CYTOCHROME C IN YEAST

Genetics ◽  
1975 ◽  
Vol 81 (4) ◽  
pp. 615-629
Author(s):  
Christopher W Lawrence ◽  
Fred Sherman ◽  
Mary Jackson ◽  
Richard A Gilmore
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
The Other ◽  
Crossing Over ◽  
Wild Type ◽  
Chromosome X ◽  
Tetrad Analysis ◽  
Yeast Saccharomyces Cerevisiae ◽  
Distal Marker ◽  
The Right

ABSTRACT We have investigated the order of the four genes cyc1, rad7, SUP4, and cdc8 which form a tightly linked cluster on the right arm of chromosome X in the yeast Saccharomyces cerevisiae. Crossing over and coconversion data from tetrad analysis established the gene order to be centromere–cyc1–rad7–SUP4. Also cdc8 appeared to be distal to SUP4 on the basis of crossovers that were associated with conversion of SUP4. The frequencies of recombination and the occurrence of coconversions suggest that these four genes are contiguous or at least nearly so. Gene-conversion frequencies for several cyc1 alleles were studied, including cyc1–1, a deletion of the whole gene that extends into the rad7 locus. The cyc1–1 deletion was found to be capable of conversion, though at a frequency some fivefold less than the other alleles studied, and both 3:1 and 1:3 events were detected. In general 1:3 and 3:1 conversion events were equally frequent at all loci studied, and approximately 50% of conversions were accompanied by reciprocal recombination for flanking markers. The orientation of the cyc1 gene could not be clearly deduced from the behavior of the distal marker SUP4 in wild-type recombinants that arose from diploids heteroallelic for cyc1 mutations.

Recombinationless meiosis in Saccharomyces cerevisiae

1981 ◽  
Vol 1 (10) ◽  
pp. 891-901
Author(s):  
R E Malone ◽  
R E Esposito
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Genetic Control ◽  
Meiotic Recombination ◽  
Meiotic Division ◽  
Crossing Over ◽  
Background Levels ◽  
Recombination System ◽  
Rad50 Gene ◽  
Meiosis I

We have utilized the single equational meiotic division conferred by the spo13-1 mutation of Saccharomyces cerevisiae (S. Klapholtz and R. E. Esposito, Genetics 96:589-611, 1980) as a technique to study the genetic control of meiotic recombination and to analyze the meiotic effects of several radiation-sensitive mutations (rad6-1, rad50-1, and rad52-1) which have been reported to reduce meiotic recombination (Game et al., Genetics 94:51-68, 1980); Prakash et al., Genetics 94:31-50, 1980). The spo13-1 mutation eliminates the meiosis I reductional segregation, but does not significantly affect other meiotic events (including recombination). Because of the unique meiosis it confers, the spo13-1 mutation provides an opportunity to recover viable meiotic products in a Rec- background. In contrast to the single rad50-1 mutant, we found that the double rad50-1 spo13-1 mutant produced viable ascospores after meiosis and sporulation. These spores were nonrecombinant: meiotic crossing-over was reduced at least 150-fold, and no increase in meiotic gene conversion was observed over mitotic background levels. The rad50-1 mutation did not, however, confer a Rec- phenotype in mitosis; rather, it increased both spontaneous crossing-over and gene conversion. The spore inviability conferred by the single rad6-1 and rad52-1 mutations was not eliminated by the presence of the spo13-1 mutation. Thus, only the rad50 gene has been unambiguously identified by analysis of viable meiotic ascospores as a component of the meiotic recombination system.

scholarly journals The Tn3 beta-lactamase gene acts as a hotspot for meiotic recombination in yeast.

Genetics ◽  
1991 ◽  
Vol 127 (1) ◽  
pp. 39-51 ◽  
Author(s):  
A Stapleton ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Sequence ◽  
Dna Sequences ◽  
Meiotic Recombination ◽  
Genetic Distances ◽  
Crossing Over ◽  
Beta Lactamase ◽  
Yeast Saccharomyces Cerevisiae ◽  
Lactamase Gene ◽  
Bacterial Transposon

Abstract Although genetic distances are often assumed to be proportional to physical distances, chromosomal regions with unusually high (hotspots) or low (coldspots) levels of meiotic recombination have been described in a number of genetic systems. In general, the DNA sequences responsible for these effects have not been determined. We report that the 5' region of the beta-lactamase (ampR) gene of the bacterial transposon Tn3 is a hotspot for meiotic recombination when inserted into the chromosomes of the yeast Saccharomyces cerevisiae. When these sequences are homozygous, both crossing over and gene conversion are locally stimulated. The 5' end of the beta-lactamase gene is about 100-fold "hotter" for crossovers than an average yeast DNA sequence.

scholarly journals The rec102 mutant of yeast is defective in meiotic recombination and chromosome synapsis.

Genetics ◽  
1992 ◽  
Vol 130 (1) ◽  
pp. 59-69
Author(s):  
J Bhargava ◽  
J Engebrecht ◽  
G S Roeder
Keyword(s):  
Synaptonemal Complex ◽  
Chromosome Segregation ◽  
Meiotic Recombination ◽  
Meiotic Chromosome ◽  
Crossing Over ◽  
Homologous Chromosomes ◽  
Chromosome Synapsis ◽  
Recombination Pathway ◽  
Yeast Mutants ◽  
Meiosis I

Abstract A mutation at the REC102 locus was identified in a screen for yeast mutants that produce inviable spores. rec102 spore lethality is rescued by a spo13 mutation, which causes cells to bypass the meiosis I division. The rec102 mutation completely eliminates meiotically induced gene conversion and crossing over but has no effect on mitotic recombination frequencies. Cytological studies indicate that the rec102 mutant makes axial elements (precursors to the synaptonemal complex), but homologous chromosomes fail to synapse. In addition, meiotic chromosome segregation is significantly delayed in rec102 strains. Studies of double and triple mutants indicate that the REC102 protein acts before the RAD52 gene product in the meiotic recombination pathway. The REC102 gene was cloned based on complementation of the mutant defect and the gene was mapped to chromosome XII between CDC25 and STE11.

scholarly journals The Role of Centromere Alignment in Meiosis I Segregation of Homologous Chromosomes in Saccharomyces cerevisiae

Genetics ◽  
1999 ◽  
Vol 153 (4) ◽  
pp. 1547-1560
Author(s):  
Cesar E Guerra ◽  
David B Kaback
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Chromosome Segregation ◽  
Meiotic Chromosome ◽  
Meiotic Spindle ◽  
Physical Interaction ◽  
Crossing Over ◽  
Homologous Chromosomes ◽  
Chromosome Alignment ◽  
Chromosome I

AbstractDuring meiosis, homologous chromosomes pair and then segregate from each other at the first meiotic division. Homologous centromeres appear to be aligned when chromosomes are paired. The role of centromere alignment in meiotic chromosome segregation was investigated in Saccharomyces cerevisiae diploids that contained one intact copy of chromosome I and one copy bisected into two functional centromere-containing fragments. The centromere on one fragment was aligned with the centromere on the intact chromosome while the centromere on the other fragment was either aligned or misaligned. Fragments containing aligned centromeres segregated efficiently from the intact chromosome, while fragments containing misaligned centromeres segregated much less efficiently from the intact chromosome. Less efficient segregation was correlated with crossing over in the region between the misaligned centromeres. Models that suggest that these crossovers impede proper segregation by preventing either a segregation-promoting chromosome alignment on the meiotic spindle or some physical interaction between homologous centromeres are proposed.

scholarly journals CHROMOSOMAL TRANSLOCATIONS GENERATED BY HIGH-FREQUENCY MEIOTIC RECOMBINATION BETWEEN REPEATED YEAST GENES

Genetics ◽  
1986 ◽  
Vol 114 (3) ◽  
pp. 731-752
Author(s):  
Sue Jinks-Robertson ◽  
Thomas D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Meiotic Recombination ◽  
High Frequency ◽  
Mitotic Recombination ◽  
Chromosomal Translocations ◽  
Yeast Saccharomyces Cerevisiae ◽  
Homologous Chromosomes ◽  
Yeast Genes ◽  
Repeated Genes

ABSTRACT We have examined meiotic and mitotic recombination between repeated genes on nonhomologous chromosomes in the yeast Saccharomyces cerevisiae . The results of these experiments can be summarized in three statements. First, gene conversion events between repeats on nonhomologous chromosomes occur frequently in meiosis. The frequency of such conversion events is only 17-fold less than the analogous frequency of conversion between genes at allelic positions on homologous chromosomes. Second, meiotic and mitotic conversion events between repeated genes on nonhomologous chromosomes are associated with reciprocal recombination to the same extent as conversion between allelic sequences. The reciprocal exchanges between the repeated genes result in chromosomal translocations. Finally, recombination between repeated genes on nonhomologous chromosomes occurs much more frequently in meiosis than in mitosis.

scholarly journals Recombinationless meiosis in Saccharomyces cerevisiae.

1981 ◽  
Vol 1 (10) ◽  
pp. 891-901 ◽  
Author(s):  
R E Malone ◽  
R E Esposito
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Genetic Control ◽  
Meiotic Recombination ◽  
Meiotic Division ◽  
Crossing Over ◽  
Background Levels ◽  
Recombination System ◽  
Rad50 Gene ◽  
Meiosis I

We have utilized the single equational meiotic division conferred by the spo13-1 mutation of Saccharomyces cerevisiae (S. Klapholtz and R. E. Esposito, Genetics 96:589-611, 1980) as a technique to study the genetic control of meiotic recombination and to analyze the meiotic effects of several radiation-sensitive mutations (rad6-1, rad50-1, and rad52-1) which have been reported to reduce meiotic recombination (Game et al., Genetics 94:51-68, 1980); Prakash et al., Genetics 94:31-50, 1980). The spo13-1 mutation eliminates the meiosis I reductional segregation, but does not significantly affect other meiotic events (including recombination). Because of the unique meiosis it confers, the spo13-1 mutation provides an opportunity to recover viable meiotic products in a Rec- background. In contrast to the single rad50-1 mutant, we found that the double rad50-1 spo13-1 mutant produced viable ascospores after meiosis and sporulation. These spores were nonrecombinant: meiotic crossing-over was reduced at least 150-fold, and no increase in meiotic gene conversion was observed over mitotic background levels. The rad50-1 mutation did not, however, confer a Rec- phenotype in mitosis; rather, it increased both spontaneous crossing-over and gene conversion. The spore inviability conferred by the single rad6-1 and rad52-1 mutations was not eliminated by the presence of the spo13-1 mutation. Thus, only the rad50 gene has been unambiguously identified by analysis of viable meiotic ascospores as a component of the meiotic recombination system.

scholarly journals Mitotic and meiotic gene conversion of Ty elements and other insertions in Saccharomyces cerevisiae.

Genetics ◽  
1989 ◽  
Vol 122 (4) ◽  
pp. 759-772
Author(s):  
A Vincent ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Point Mutations ◽  
Crossing Over ◽  
Yeast Saccharomyces Cerevisiae ◽  
Ty Elements ◽  
Meiotic Gene ◽  
Mitotic Gene Conversion

Abstract We examined meiotic and mitotic gene conversion events involved in deletion of Ty elements and other insertions from the genome of the yeast Saccharomyces cerevisiae. We found that Ty elements and one other insertion were deleted by mitotic gene conversion less frequently than point mutations at the same loci. One non-Ty insertion similar in size to Ty, however, did not show this bias. Mitotic conversion events deleting insertions were more frequently associated with crossing over than those deleting point mutations. In meiosis, conversion events duplicating the element were more common than those that deleted the element for one of the loci (HIS4) examined.

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