MEIOTIC CHROMOSOME BEHAVIOR OF AN INVERTED INSERTIONAL TRANSLOCATION IN NEUROSPORA

Genetics ◽  
1972 ◽  
Vol 71 (1) ◽  
pp. 53-62
Author(s):  
Edward G Barry
Keyword(s):  
Linkage Group ◽  
Meiotic Chromosome ◽  
Chromosome 1 ◽  
Homologous Region ◽  
Supporting Evidence ◽  
Type Locus ◽  
Anaphase Bridges ◽  
Meiotic Chromosomes ◽  
Group I ◽  
New Location

ABSTRACT Cytological study of meiotic chromosomes heterozygous for the T(I⇉II)39311 translocation confirm genetic evidence (Perkins 1972) that a section of linkage group I including the mating type locus has been inserted into linkage group II. Pachytene chromosomes when fully paired show that a segment from chromosome 1 has been inserted into chromosome 6. When pairing fails between the translocated segment in 6 and its homologous region in chromosome 1, buckles or loops are formed at pachynema in the deletion or insertion areas of the bivalents.—Acentric fragments and anaphase bridges occur at both meiotic divisions and in the subsequent two mitotic divisions in the ascus. These provide supporting evidence that the translocated segment is inverted with respect to centromere in its new location.—Unexpectedly the acentric fragment, formed by crossing over in the inverted translocated segment, persists without degradation in a micronucleus, and it replicates and divides in synchrony with the centric chromosomes in adjacent nuclei.

scholarly journals REVERSAL OF A NEUROSPORA TRANSLOCATION BY CROSSING OVER INVOLVING DISPLACED rDNA, AND METHYLATION OF THE rDNA SEGMENTS THAT RESULT FROM RECOMBINATION

Genetics ◽  
1986 ◽  
Vol 114 (3) ◽  
pp. 791-817
Author(s):  
David D Perkins ◽  
Robert L Metzenberg ◽  
Namboori B Raju ◽  
Eric U Selker ◽  
Edward G Barry
Keyword(s):  
Linkage Group ◽  
Distal Portion ◽  
Nucleolus Organizer ◽  
Rrna Genes ◽  
Molecular Evidence ◽  
Crossing Over ◽  
Wild Type ◽  
Type Locus ◽  
Group I ◽  
Chromosome Sequence

ABSTRACT In translocation OY321 of Neurospora crassa, the nucleolus organizer is divided into two segments, a proximal portion located interstitially in one interchange chromosome, and a distal portion now located terminally on another chromosome, linkage group I. In crosses of Translocation x Translocation, exceptional progeny are recovered nonselectively in which the chromosome sequence has apparently reverted to Normal. Genetic, cytological, and molecular evidence indicates that reversion is the result of meiotic crossing over between homologous displaced rDNA repeats. Marker linkages are wild type in these exceptional progeny. They differ from wild type, however, in retaining an interstitial block of rRNA genes which can be demonstrated cytologically by the presence of a second, small interstitial nucleolus and genetically by linkage of an rDNA restriction site polymorphism to the mating-type locus in linkage group I. The interstitial rDNA is more highly methylated than the terminal rDNA. The mechanism by which methylation enzymes distinguish between interstitial rDNA and terminal rDNA is unknown. Some hypotheses are considered.

Meiotic analysis of induced mutations in Ophiostoma ulmi

1990 ◽  
Vol 68 (2) ◽  
pp. 232-235 ◽  
Author(s):  
L. Bernier ◽  
M. Hubbes
Keyword(s):  
Linkage Group ◽  
Dutch Elm Disease ◽  
Induced Mutations ◽  
Type Locus ◽  
Meiotic Analysis ◽  
Ophiostoma Ulmi ◽  
Group I ◽  
Disease Mutations ◽  
Nuclear Mutations ◽  
Additional Locus

Laboratory strains of Ophiostoma ulmi carrying nuclear mutations induced by exposure to N-methyl-N′-nitro-N-nitrosoguanidine were crossed, and the segregation of genetic markers was analyzed in random ascospore progeny. Investigation of 13 auxotrophic mutations and 1 benomyl-resistant mutation provided evidence for at least three linkage groups in O. ulmi. Five loci, identified by mutant alleles ade1-1, BENIR-1, cyi1-1, lys3-1, and nic1-1, were assigned to linkage group I, whereas markers ade2-1 and lys2-2 were mapped on linkage group II. An additional locus, Met1, was assigned to a third linkage group since mutant alleles at this locus segregated independently from markers on group I or II. The Ben1R locus, controlling resistance to benomyl, segregated independently from the mating type locus and thus appeared to differ from the Tol locus described by other workers. Key words: Ophiostoma ulmi, Dutch elm disease, mutations, linkage analysis.

Homogeneously Staining Regions (HSR) in Chromosome 1 of the House Mouse: Synapsis and Recombination at Meiosis

2021 ◽  
pp. 1-9
Author(s):  
Nikita Y. Torgunakov ◽  
Elena A. Kizilova ◽  
Tatyana V. Karamysheva ◽  
Lyubov P. Malinovskaya ◽  
Tatiana I. Bikchurina ◽  
...  
Keyword(s):  
Long Range ◽  
House Mouse ◽  
Epigenetic Modification ◽  
Meiotic Chromosome ◽  
Natural Populations ◽  
Chromosome 1 ◽  
Recombination Nodules ◽  
Meiotic Chromosomes ◽  
Mus Musculus Musculus ◽  
Mlh1 Foci

Amplified sequences constitute a large part of mammalian genomes. A chromosome 1 containing 2 large (up to 50 Mb) homogeneously staining regions (HSRs) separated by a small inverted euchromatic region is present in many natural populations of the house mouse (Mus musculus musculus). The HSRs are composed of a long-range repeat cluster, Sp100-rs, with a repeat length of 100 kb. In order to understand the organization and function of HSRs in meiotic chromosomes, we examined synapsis and recombination in male mice hetero- and homozygous for the HSR-carrying chromosome using FISH with an HSR-specific DNA probe and immunolocalization of the key meiotic proteins. In all homozygous and heterozygous pachytene nuclei, we observed fully synapsed linear homomorphic bivalents 1 marked by the HSR FISH probe. The synaptic adjustment in the heterozygotes was bilateral: the HSR-carrying homolog was shortened and the wild-type homolog was elongated. The adjustment was reversible: desynapsis at diplotene was accompanied by elongation of the HSRs. Immunolocalization of H3K9me2/3 indicated that the HSRs in the meiotic chromosome retained the epigenetic modification typical for C-heterochromatin in somatic cells. MLH1 foci, marking mature recombination nodules, were detected in the proximal HSR band in heterozygotes and in both HSR bands of homozygotes. Unequal crossing over within the long-range repeat cluster can cause variation in size of the HSRs, which has been detected in the natural populations of the house mouse.

scholarly journals Molecular organization of mammalian meiotic chromosome axis revealed by expansion STORM microscopy

2019 ◽  
Vol 116 (37) ◽  
pp. 18423-18428 ◽  
Author(s):  
Huizhong Xu ◽  
Zhisong Tong ◽  
Qing Ye ◽  
Tengqian Sun ◽  
Zhenmin Hong ◽  
...  
Keyword(s):  
Meiotic Chromosome ◽  
Molecular Organization ◽  
Homologous Chromosomes ◽  
Meiotic Chromosomes ◽  
C Terminus ◽  
Stochastic Optical Reconstruction Microscopy ◽  
Optical Reconstruction ◽  
20 Nm ◽  
Chromosome Axis

During prophase I of meiosis, chromosomes become organized as loop arrays around the proteinaceous chromosome axis. As homologous chromosomes physically pair and recombine, the chromosome axis is integrated into the tripartite synaptonemal complex (SC) as this structure’s lateral elements (LEs). While the components of the mammalian chromosome axis/LE—including meiosis-specific cohesin complexes, the axial element proteins SYCP3 and SYCP2, and the HORMA domain proteins HORMAD1 and HORMAD2—are known, the molecular organization of these components within the axis is poorly understood. Here, using expansion microscopy coupled with 2-color stochastic optical reconstruction microscopy (STORM) imaging (ExSTORM), we address these issues in mouse spermatocytes at a resolution of 10 to 20 nm. Our data show that SYCP3 and the SYCP2 C terminus, which are known to form filaments in vitro, form a compact core around which cohesin complexes, HORMADs, and the N terminus of SYCP2 are arrayed. Overall, our study provides a detailed structural view of the meiotic chromosome axis, a key organizational and regulatory component of meiotic chromosomes.

scholarly journals Glycoproteins that exhibit extensive size polymorphisms in Dictyostelium discoideum.

Genetics ◽  
1989 ◽  
Vol 122 (1) ◽  
pp. 59-64 ◽  
Author(s):  
E Smith ◽  
A A Gooley ◽  
G C Hudson ◽  
K L Williams
Keyword(s):  
Linkage Group ◽  
Dictyostelium Discoideum ◽  
Allelic Variation ◽  
Surface Glycoprotein ◽  
Developmentally Regulated ◽  
Electrophoretic Variants ◽  
Cellular Slime Mould ◽  
Repeat Units ◽  
Group I ◽  
Cellular Slime

Abstract Electrophoretic variants which arise from amino acid substitutions, leading to charge differences between proteins are ubiquitous and have been used extensively for genetic analysis. Less well documented are polymorphisms in the size of proteins. Here we report that a group of glycoproteins, which share a common carbohydrate epitope, vary in size in different isolates of the cellular slime mould, Dictyostelium discoideum. One of these proteins, PsA, a developmentally regulated prespore-specific surface glycoprotein, has previously been shown to exist in three size forms due to allelic variation at the pspA locus on linkage group I. In this report, a second glycoprotein, PsB, which is also prespore specific but found inside prespore cells, is studied. PsB maps to linkage group II and exhibits at least four different sizes in the isolates examined. We propose that the size polymorphisms are the product of allelic variation at the pspB locus, due to differences in the number of repeat units.

NEW DUPLICATION-GENERATING INVERSIONS IN NEUROSPORA

1969 ◽  
Vol 11 (3) ◽  
pp. 622-638 ◽  
Author(s):  
Barbara C. Turner ◽  
Cecile W. Taylor ◽  
David D. Perkins ◽  
Dorothy Newmeyer
Keyword(s):  
Mating Type ◽  
Break Point ◽  
Low Fertility ◽  
Type Locus ◽  
Complementary Product ◽  
Single Crossing ◽  
Group I ◽  
Distinctive Morphology ◽  
Phenotype Characteristic ◽  
Break Points

Inversion In(ILR)NM176 has one break point at the extreme right end of linkage group I and the other distal to mating type in the left arm. In crosses of Inversion × Normal the products of single crossing over within the inversion are complementary duplication-deficiency classes. One crossover product is viable, with a large segment of IL duplicated and the dispensable right tip presumably deficient. This class has low fertility and distinctive morphology. The complementary product has a large deficiency which results in a pair of white, inviable ascospores. Single exchanges within the heterozygous inversion thus produce asci with 6 Black: 2 White spores; four-strand double exchanges produce 4 B:4 W; and non-exchanges produce asci with 8 B:0 W. Approximate mapping of break points was accomplished by three-point crosses. Precise placement of the left break point between ser-3 and un(55701t), just left of mating type, is based on coverage of markers by the heterozygous duplication. No crossover has been obtained between mating type and the break point, despite extensive efforts. In(ILR)NM176 differs from the inversion In(ILR)H4250 described by Newmeyer and Taylor (1967) in one main respect: the mating type locus is included in the inverted segment of NM176. Consequently, when duplications are generated, the progeny are unisexual and do not have the unstable inhibited phenotype characteristic of H4250 duplication progeny, which are heterozygous for the mating type alleles A and a. Three other inversions which originated independently of In(ILR)NM176 resemble it closely and have similar or identical break points.

Linkage Analysis of Sex Determination in Bracon sp. Near hebetor (Hymenoptera: Braconidae)

Genetics ◽  
2000 ◽  
Vol 154 (1) ◽  
pp. 205-212
Author(s):  
Alisha K Holloway ◽  
Michael R Strand ◽  
William C Black ◽  
Michael F Antolin
Keyword(s):  
Linkage Group ◽  
Sex Determination ◽  
Rapd Markers ◽  
Random Amplified Polymorphic Dna ◽  
Parasitic Wasp ◽  
Specific Pattern ◽  
Diploid Males ◽  
Phenotypic Marker ◽  
Group I ◽  
Sex Locus

Abstract To test whether sex determination in the parasitic wasp Bracon sp. near hebetor (Hymenoptera: Braconidae) is based upon a single locus or multiple loci, a linkage map was constructed using random amplified polymorphic DNA (RAPD) markers. The map includes 71 RAPD markers and one phenotypic marker, blonde. Sex was scored in a manner consistent with segregation of a single “sex locus” under complementary sex determination (CSD), which is common in haplodiploid Hymenoptera. Under haplodiploidy, males arise from unfertilized haploid eggs and females develop from fertilized diploid eggs. With CSD, females are heterozygous at the sex locus; diploids that are homozygous at the sex locus become diploid males, which are usually inviable or sterile. Ten linkage groups were formed at a minimum LOD of 3.0, with one small linkage group that included the sex locus. To locate other putative quantitative trait loci (QTL) for sex determination, sex was also treated as a binary threshold character. Several QTL were found after conducting permutation tests on the data, including one on linkage group I that corresponds to the major sex locus. One other QTL of smaller effect had a segregation pattern opposite to that expected under CSD, while another putative QTL showed a female-specific pattern consistent with either a sex-differentiating gene or a sex-specific deleterious mutation. Comparisons are made between this study and the indepth studies on sex determination and sex differentiation in the closely related B. hebetor.

scholarly journals A molecular model for the role of SYCP3 in meiotic chromosome organisation

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Johanna Liinamaria Syrjänen ◽  
Luca Pellegrini ◽  
Owen Richard Davies
Keyword(s):  
Molecular Model ◽  
Meiotic Chromosome ◽  
Lateral Element ◽  
Homologous Chromosomes ◽  
Meiotic Chromosomes ◽  
Double Stranded Dna ◽  
Evolutionarily Conserved ◽  
20 Nm ◽  
Chromosome Organisation

The synaptonemal complex (SC) is an evolutionarily-conserved protein assembly that holds together homologous chromosomes during prophase of the first meiotic division. Whilst essential for meiosis and fertility, the molecular structure of the SC has proved resistant to elucidation. The SC protein SYCP3 has a crucial but poorly understood role in establishing the architecture of the meiotic chromosome. Here we show that human SYCP3 forms a highly-elongated helical tetramer of 20 nm length. N-terminal sequences extending from each end of the rod-like structure bind double-stranded DNA, enabling SYCP3 to link distant sites along the sister chromatid. We further find that SYCP3 self-assembles into regular filamentous structures that resemble the known morphology of the SC lateral element. Together, our data form the basis for a model in which SYCP3 binding and assembly on meiotic chromosomes leads to their organisation into compact structures compatible with recombination and crossover formation.

Linkage group I: the simultaneous estimation of recombination and interference

1976 ◽  
Vol 16 (1-5) ◽  
pp. 335-339 ◽  
Author(s):  
D.A. Meyers ◽  
P.M. Conneally ◽  
E.W. Lovrien ◽  
E. Magenis ◽  
A.D. Merritt ◽  
...  
Keyword(s):  
Linkage Group ◽  
Simultaneous Estimation ◽  
Group I

scholarly journals Localization of RAP1 and topoisomerase II in nuclei and meiotic chromosomes of yeast

1992 ◽  
Vol 117 (5) ◽  
pp. 935-948 ◽  
Author(s):  
F Klein ◽  
T Laroche ◽  
ME Cardenas ◽  
JF Hofmann ◽  
D Schweizer ◽  
...  
Keyword(s):  
Topoisomerase Ii ◽  
Meiotic Chromosome ◽  
Nuclear Periphery ◽  
Yeast Cells ◽  
Activator Protein 1 ◽  
Interphase Nuclei ◽  
Telomeric Sequences ◽  
Meiotic Chromosomes ◽  
Punctate Staining

Topoisomerase II (topoII) and RAP1 (Repressor Activator Protein 1) are two abundant nuclear proteins with proposed structural roles in the higher-order organization of chromosomes. Both proteins co-fractionate as components of nuclear scaffolds from vegetatively growing yeast cells, and both proteins are present as components of pachytene chromosome, co-fractionating with an insoluble subfraction of meiotic nuclei. Immunolocalization using antibodies specific for topoII shows staining of an axial core of the yeast meiotic chromosome, extending the length of the synaptonemal complex. RAP1, on the other hand, is located at the ends of the paired bivalent chromosomes, consistent with its ability to bind telomeric sequences in vitro. In interphase nuclei, again in contrast to anti-topoII, anti-RAP1 gives a distinctly punctate staining that is located primarily at the nuclear periphery. Approximately 16 brightly staining foci can be identified in a diploid nucleus stained with anti-RAP1 antibodies, suggesting that telomeres are grouped together, perhaps through interaction with the nuclear envelope.

Sign in / Sign up

Export Citation Format

Share Document