scholarly journals Multilocus half-tetrad analysis and centromere mapping in citrus: evidence of SDR mechanism for 2n megagametophyte production and partial chiasma interference in mandarin cv ‘Fortune’

Heredity ◽  
2011 ◽  
Vol 107 (5) ◽  
pp. 462-470 ◽  
Author(s):  
J Cuenca ◽  
Y Froelicher ◽  
P Aleza ◽  
J Juárez ◽  
L Navarro ◽  
...  
Keyword(s):  
Tetrad Analysis ◽  
Chiasma Interference

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 A Genetic Map of Gibberella fujikuroi Mating Population A (Fusarium moniliforme)

Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 175-189 ◽  
Author(s):  
Jin-rong Xu ◽  
John F Leslie
Keyword(s):  
Fusarium Moniliforme ◽  
Fragment Length Polymorphism ◽  
Fumonisin B1 ◽  
Gibberella Fujikuroi ◽  
Female Sterility ◽  
Rflp Markers ◽  
Linkage Groups ◽  
Mating Population ◽  
Spore Killer ◽  
Chiasma Interference

Abstract We constructed a recombination-based map of the fungal plant pathogen Gibberella fujikuroi mating population A (asexual stage Fusarium moniliforme). The map is based on the segregation of 142 restriction fragment length polymorphism (RFLP) markers, two auxotrophic genes (arg1, nic1), mating type (matA+ / matA−), female sterility (ste1), spore-killer (Sk), and a gene governing the production of the mycotoxin fumonisin B1 (fum1) among 121 random ascospore progeny from a single cross. We identified 12 linkage groups corresponding to the 12 chromosome-sized DNAs previously observed in contour-clamped homogeneous electric field (CHEF) gels. Linkage groups and chromosomes were correlated via Southern blots between appropriate RFLP markers and the CHEF gels. Eleven of the 12 chromosomes are meiotically stable, but the 12th (and smallest) is subject to deletions in 3% (4/121) of the progeny. Positive chiasma interference occurred on five of the 12 chromosomes, and nine of the 12 chromosomes averaged more than one crossover per chromosome. The average kb/cM ratio in this cross is ~32.

scholarly journals Statistical Analysis of Ordered Tetrads

Genetics ◽  
1998 ◽  
Vol 150 (1) ◽  
pp. 459-472 ◽  
Author(s):  
Hongyu Zhao ◽  
Terence P Speed
Keyword(s):  
Statistical Analysis ◽  
Genetic Markers ◽  
Chi Square ◽  
Yield Information ◽  
Data Yield ◽  
Interference Models ◽  
Chiasma Interference

Abstract Ordered tetrad data yield information on chromatid interference, chiasma interference, and centromere locations. In this article, we show that the assumption of no chromatid interference imposes certain constraints on multilocus ordered tetrad probabilities. Assuming no chromatid interference, these constraints can be used to order markers under general chiasma processes. We also derive multilocus tetrad probabilities under a class of chiasma interference models, the chi-square models. Finally, we compare centromere map functions under the chi-square models with map functions proposed in the literature. Results in this article can be applied to order genetic markers and map centromeres using multilocus ordered tetrad data.

Use of half-tetrad analysis to discriminate between two types of 2n egg formation in a potato haploid

Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 741-745 ◽  
Author(s):  
Joanna E. Werner ◽  
David S. Douches ◽  
Rosanna Freyre
Keyword(s):  
Solanum Tuberosum L ◽  
2N Gametes ◽  
Breeding Value ◽  
Tetrad Analysis ◽  
Recombination Rates ◽  
First Division Restitution ◽  
Egg Formation ◽  
Second Division Restitution ◽  
2N Eggs ◽  
Tetraploid Progeny

The ratio of the first division restitution (FDR) to second division restitution (SDR) 2n eggs was estimated in 4182t, a haploid (2n = 2x = 24) of Solanum tuberosum L. that produces 2n eggs by the two modes. The segregation of three genes previously mapped relative to their centromeres, Pgm-2 (2.0 cM), Mdh-1 (33.5 cM), and 6-Pgdh-3 (30.1 cM) was analyzed in the tetraploid offspring of a 2x × 4x cross. Based on the segregation of the Pgm-2 locus, 39.7% of the progeny originated from FDR 2n eggs and 60.3% from SDR. Segregation patterns of the two distal loci within the FDR-derived 4x subpopulation indicated that the gene–centromere recombination rate during megasporogenesis was significantly reduced for Mdh-1 when compared with a previous estimate during microsporogenesis. In the SDR-derived 4x subpopulation, the gene–centromere recombination rates for Mdh-1 and 6-Pgdh-3 were not significantly different from previous estimates. Tetraploid progeny generated from one 2x × 4x cross where the 2x parent produces 2n gametes by two modes can be used to make an unbiased comparison of the potential breeding value of FDR and SDR gametes.Key words: potato, megasporogenesis, first division restitution, second division restitution, isozyme.

scholarly journals The intron-containing gene for yeast profilin (PFY) encodes a vital function

1988 ◽  
Vol 8 (12) ◽  
pp. 5108-5115
Author(s):  
V Magdolen ◽  
U Oechsner ◽  
G Müller ◽  
W Bandlow
Keyword(s):  
Diploid Cell ◽  
Single Copy ◽  
Actin Binding ◽  
Gene Copy ◽  
Tetrad Analysis ◽  
Vital Function ◽  
Primary Transcript ◽  
Gene Coding ◽  
Gene Maps ◽  
Coding Capacity

The gene coding for profilin (PFY), an actin-binding protein, occurs as a single copy in the haploid genome of Saccharomyces cerevisiae and is required for spore germination and cell viability. Displacement of one gene copy in a diploid cell by a nonfunctional allele is recessively lethal: tetrad analysis yields only two viable spores per ascus. The PFY gene maps on chromosome XV and is linked to the ADE2 marker. The primary transcript of about 1,000 bases contains an intron of 209 bases and is spliced into a messenger of about 750 bases. The intron was identified by comparison with a cDNA clone, which also revealed the 3' end of the transcript. The 5' end of the mRNA was mapped by primer elongation. The gene is transcribed constitutively and has a coding capacity for a protein of 126 amino acids. The deduced molecular weight of

scholarly journals DeepTetrad: high-throughput analysis of meiotic tetrads by deep learning in plants

2019 ◽  
Author(s):  
Eun-Cheon Lim ◽  
Jaeil Kim ◽  
Jihye Park ◽  
Eun-Jung Kim ◽  
Juhyun Kim ◽  
...  
Keyword(s):  
Deep Learning ◽  
Chromosome Segregation ◽  
High Throughput ◽  
Fluorescent Protein ◽  
Genetic Dissection ◽  
Crossover Frequency ◽  
Tetrad Analysis ◽  
High Throughput Analysis ◽  
Crossover Interference ◽  
Pollen Tetrad

AbstractMeiotic crossovers facilitate chromosome segregation and create new combinations of alleles in gametes. Crossover frequency varies along chromosomes and crossover interference limits the coincidence of closely spaced crossovers. Crossovers can be measured by observing the inheritance of linked transgenes expressing different colors of fluorescent protein in Arabidopsis pollen tetrads. Here we establish DeepTetrad, a deep learning-based image recognition package for pollen tetrad analysis that enables high-throughput measurements of crossover frequency and interference in individual plants. DeepTetrad will accelerate genetic dissection of mechanisms that control meiotic recombination.

Ethylene−Norbornene Copolymers byCs-Symmetric Metallocenes:  Determination of the Copolymerization Parameters and Mechanistic Considerations on the Basis of Tetrad Analysis

2005 ◽  
Vol 38 (24) ◽  
pp. 9910-9919 ◽  
Author(s):  
Incoronata Tritto ◽  
Laura Boggioni ◽  
Cristina Zampa ◽  
Dino R. Ferro
Keyword(s):  
Tetrad Analysis
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