Chicken Microchromosomes in the Lampbrush Phase: A Cytogenetic Description

2017 ◽  
Vol 152 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Svetlana Galkina ◽  
Valerie Fillon ◽  
Alsu Saifitdinova ◽  
Aleksandra Daks ◽  
Maria Kulak ◽  
...  
Keyword(s):  
Lampbrush Chromosomes ◽  
Linkage Groups ◽  
Cytogenetic Mapping ◽  
Convenient Tool ◽  
Meiotic Chromosomes ◽  
Lateral Loop

Lampbrush chromosomes are giant, transcriptionally active, meiotic chromosomes found in oocytes of all vertebrates with the exception of mammals. Lampbrush chromosomes offer a convenient tool for cytogenetic mapping and, in particular, have been instrumental in mapping genes and linkage groups on chicken (GGA) chromosomes. Whereas cytogenetic maps of macrochromosome GGA1-10 and microchromosome GGA11-16 lampbrush bivalents have been established, identification and description of smaller microchromosome bivalents are still missing. In this work, we used specific FISH probes for the identification of 12 chicken lampbrush chromosomes formed by GGA17-28. Our observations on chromomere and lateral loop arrangement and chiasma position allowed us to construct the respective cytogenetic maps for these microchromosomes. For the 10 smallest chicken microchromosomes, GGA29-38, no individual molecular tags are available, yet they can be collectively marked using the PO41 repeat. The reported results contribute to building of working cytogenetic maps of the chicken karyotype.

The Actions of Enzymes on Lampbrush Chromosomes

1962 ◽  
Vol s3-103 (62) ◽  
pp. 173-203
Author(s):  
H. C. MACGREGOR ◽  
H. G. CALLAN
Keyword(s):  
Proteolytic Enzymes ◽  
Lampbrush Chromosomes ◽  
Triturus Cristatus ◽  
Trichloracetic Acid ◽  
Protease Digestion ◽  
Lateral Loop ◽  
Peptic Digestion ◽  
Rnase Digestion ◽  
Break Chromosome ◽  
Loop Matrix

The chromomeres of lampbrush chromosomes of Triturus cristatus are Feulgen-positive; they therefore contain DNA. After removal of their DNA in boiling trichloracetic acid, the chromomeres stain with fast green at alkaline pH; they therefore contain basic protein. The lateral loops are Feulgen-negative; they stain with toluidine blue at acid pH, but much less intensely following RNase digestion; they therefore contain RNA. The spheres of chromosomes V and VIII do not contain RNA. Unfixed lampbrush chromosomes retain a life-like appearance in 0.07 M K/NaCl at pH 6.2; in this medium the nuclear sap disperses. As pH is raised to 8.5 the matrices of lateral loops dissolve but chromosome axes remain unbroken. Above pH 8.5 lampbrush chromosomes dissolve. As pH is lowered from 6.2, at between 5.8 and 5.4 coagulation occurs. If pH is rapidly reduced still further, a persistent relaxed condition sets in between 2.5 and 2. In concentrations of K/NaCl above 0.5 M lampbrush chromosomes dissolve. Lateral loop matrices dissolve in 0.25 M K/NaCl but chromosome axes remain unbroken. In concentrations of K/NaCl below 0.05 M lateral loop matrices dissolve, but even in distilled water chromosome axes remain unbroken. Trypsin at pH 6.2 and at pH 7.8 strips the matrices from lateral loops and occasionally breaks matrix fusions. It causes chromomeres to swell and coalesce, but fails to break chromosome axes. The action of ‘pan-protease’ resembles that of trypsin in all respects. Pepsin at pH 6.2 strips the matrices from lateral loops, but does not destroy chromomeres. At low pH peptic digestion is slow: the enzyme is attacking coagulated chromosomes; but if peptic digestion precedes a lowering of pH the overall outcome is a rapid solution of loop matrix, and under these conditions matrix and sphere fusions are broken. If trypsin or ‘pan-protease’ digestion precedes a lowering of pH there is a similarly rapid solution of loop matrix; thus the action is not specifically referable to pepsin. Under no conditions does pepsin break the axes of lampbrush chromosomes. RNase at pH 6.2 strips the matrices from lateral loops; this action is detectable at extreme dilution. RNase does not destroy chromomeres, nor does it break chromosome axes. If tryptic digestion follows RNase digestion this too fails to break chromosome axes. Unlike the proteolytic enzymes and RNase, DNase at pH 6.2 breaks the fibril between adjacent chromomeres, and it also breaks the axes of lateral loops. Contrary to Mazia's experience with salivary gland chromosomes, versene does not break the axes of lampbrush chromosomes even when applied in media of low electrolyte concentration. These results indicate that uninterrupted fibres of DNA run throughout the lengths of lampbrush chromosomes.

scholarly journals Comparison of the somatic TADs and lampbrush chromomere-loop complexes in transcriptionally active prophase I oocytes

2021 ◽  
Author(s):  
Tatiana Kulikova ◽  
Antonina Maslova ◽  
Polina Starshova ◽  
Juan Sebastian Rodriguez ◽  
Alla Krasikova
Keyword(s):  
Early Embryo ◽  
Lampbrush Chromosomes ◽  
Protein Coding ◽  
Meiotic Chromosomes ◽  
Non Coding Rna ◽  
Genomic Regions ◽  
Nascent Transcripts ◽  
Loop Domains ◽  
Embryonic Fibroblast ◽  
Rna Genes

In diplotene oocyte nuclei of all vertebrate species, except mammals, chromosomes lack interchromosomal contacts and chromatin is linearly compartmentalized into distinct chromomere-loop complexes forming lampbrush chromosomes. However, the mechanisms underlying the formation of chromomere-loop complexes remain unexplored. Here we aimed to juxtapose somatic topologically associating domains (TADs), recently identified in chicken embryonic fibroblasts, with chromomere-loop complexes in lampbrush meiotic chromosomes. By measuring 3D-distances and colocalization between linear equidistantly located genomic loci, positioned within one TAD or separated by a TAD border, we confirmed the presence of predicted TADs in chicken embryonic fibroblast nuclei. Using three-colored FISH with BAC probes we mapped equidistant genomic regions included in several sequential somatic TADs on isolated chicken lampbrush chromosomes. Eight genomic regions, each comprising two or three somatic TADs, were mapped to non-overlapping neighboring lampbrush chromatin domains - lateral loops, chromomeres or chromomere-loop complexes. Genomic loci from the neighboring somatic TADs could localize in one lampbrush chromomere-loop complex, while genomic loci belonging to the same somatic TAD could be localized in neighboring lampbrush chromomere-loop domains. In addition, FISH-mapping of BAC probes to the nascent transcripts on the lateral loops indicates transcription of at least 17 protein-coding genes and 2 non-coding RNA genes during the lampbrush stage of chicken oogenesis, including genes involved in oocyte maturation and early embryo development.

Localization of histone gene transcripts in newt lampbrush chromosomes by in situ hybridization

1977 ◽  
Vol 27 (1) ◽  
pp. 57-79
Author(s):  
R.W. Old ◽  
G.H. Callan ◽  
K.W. Gross
Keyword(s):  
Dna Sequences ◽  
Histone Gene ◽  
Lampbrush Chromosomes ◽  
Rna Sequences ◽  
Psammechinus Miliaris ◽  
Lateral Loop ◽  
Gene Transcripts ◽  
Label Distribution ◽  
Chromosome I

Denatured 3H-labelled DNAs containing histone gene sequences originating from the echinoderms Psammechinus miliaris, Echimus esculentus and Strongylocentrotus purpuratus have been in situ hybridized to RNA transcripts on newt lampbrush chromosomes. Autoradiographs of the hybridized lampbrush preparations show labelling restricted to four or fewer lateral loop pairs all lying within the heteromorphic regions of chromosome I, also one or two loop pairs on chromosome VI, one loop pair on chromosome X and one loop pair on chromosome XI. For oocytes from a single newt, coincident label distribution is found with DNA's of diverse echinoderm origin; however different newts show some specific individual diversity in label distribution, including heterozygosity in the case of loops on bivalents VI and X. The more conspicuously labelled loops, particularly those on chromosome I, show a pattern of labelling which is explicable if the newt histone DNA sequences are confined to short intercepts of lateral loop axis. Transcription is initiated prior to the histone DNA sequences, proceeds through the histone DNA sequences, and beyond, and the histone RNA sequences are cut from the transcripts before the termination of transcription.

scholarly journals Genetic and Cytogenetic Mapping of DMI1, DMI2, and DMI3 Genes of Medicago truncatula Involved in Nod Factor Transduction, Nodulation, and Mycorrhization

2002 ◽  
Vol 15 (11) ◽  
pp. 1108-1118 ◽  
Author(s):  
Jean-Michel Ané ◽  
Julien Lévy ◽  
Philippe Thoquet ◽  
Olga Kulikova ◽  
Françoise de Billy ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Fluorescent In Situ Hybridization ◽  
Fragment Length Polymorphism ◽  
Bulked Segregant Analysis ◽  
Linkage Groups ◽  
Cytogenetic Mapping ◽  
Nod Factor ◽  
Amplification Fragment Length Polymorphism ◽  
Cytogenetic Studies

The DMI1, DMI2, and DMI3 genes of Medicago truncatula, which are required for both nodulation and mycorrhization, control early steps of Nod factor signal transduction. Here, we have used diverse approaches to pave the way for the map-based cloning of these genes. Molecular amplification fragment length polymorphism markers linked to the three genes were identified by bulked segregant analysis. Integration of these markers into the general genetic map of M. truncatula revealed that DMI1, DMI2, and DMI3 are located on linkage groups 2, 5, and 8, respectively. Cytogenetic studies using fluorescent in situ hybridization (FISH) on mitotic and pachytene chromosomes confirmed the location of DMI1, DMI2, and DMI3 on chromosomes 2, 5, and 8. FISH-pachytene studies revealed that the three genes are in euchromatic regions of the genome, with a ratio of genetic to cytogenetic distances between 0.8 and 1.6 cM per μm in the DMI1, DMI2, and DMI3 regions. Through grafting experiments, we showed that the genetic control of the dmi1, dmi2, and dmi3 nodulation phenotypes is determined at the root level. This means that mutants can be transformed by Agrobacterium rhizogenes to accelerate the complementation step of map-based cloning projects for DMI1, DMI2, and DMI3.

scholarly journals Comparison of active transcription regions of lampbrush chromosomes with the mitotic chromosome G pattern in the European domestic goose <i>Anser anser</i>

2011 ◽  
Vol 54 (1) ◽  
pp. 69-82
Author(s):  
K. Andraszek ◽  
E. Smalec
Keyword(s):  
Mitotic Chromosome ◽  
Complete Information ◽  
Lampbrush Chromosomes ◽  
Sources Of Information ◽  
Mitotic Chromosomes ◽  
Anser Anser ◽  
Transcription Activity ◽  
Meiotic Chromosomes ◽  
Dividing Cells ◽  
Active Transcription

Abstract. The most complete information on the karyotype is acquired through the observation of chromosomes obtained from dividing cells. A high number of chromosomes and the presence of microchromosomes in the bird karyotype have made cytogeneticists look for other sources of information on chromosomes. Information sources of great value for the bird karyotype analysis are meiotic chromosomes, specifically represented by lampbrush chromosomes. Lampbrush chromosomes (LBCs) found in developing oocytes of birds are perceived as a new model in cytogenetics which is especially important in the analysis of bird chromosomes. A typical LBC analysis enables one to assess transcription activity on the basis of LBC morphology (inactive chromomeres and side loops). A comparison of lampbrush chromosome transcription activity and the GTG pattern of the corresponding mitotic chromosomes have proven that active transcription regions with side loops correspond to G-positive bands on mitotic chromosomes.

Implementing molecular marker technology in forage improvement

2003 ◽  
pp. 229-238
Author(s):  
M. Faville ◽  
B. Barrett ◽  
A. Griffiths ◽  
M. Schreiber ◽  
C. Mercer ◽  
...  
Keyword(s):  
Quantitative Trait Locus ◽  
Genetic Variation ◽  
White Clover ◽  
Simple Sequence Repeat ◽  
Sequence Repeat ◽  
Linkage Groups ◽  
Seedling Vigour ◽  
Genome Map ◽  
Trait Locus ◽  
Simple Sequence

Accelerated improvement of two cornerstones of New Zealand's pastoral industries, per ennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), may be realised through the application of markerassisted selection (MAS) strategies to enhance traditional plant breeding programmes. Genome maps constructed using molecular markers represent the enabling technology for such strategies and we have assembled maps for each species using EST-SSR markers - simple sequence repeat (SSR) markers developed from expressed sequence tags (ESTs) representing genes. A comprehensive map of the white clover genome has been completed, with 464 EST-SSR and genomic SSR marker loci spanning 1125 cM in total, distributed across 16 linkage groups. These have been further classified into eight pairs of linkage groups, representing contributions from the diploid progenitors of this tetraploid species. In perennial ryegrass a genome map based exclusively on EST-SSR loci was constructed, with 130 loci currently mapped to seven linkage groups and covering a distance of 391 cM. This map continues to be expanded with the addition of ESTSSR loci, and markers are being concurrently transferred to other populations segregating for economically significant traits. We have initiated gene discovery through quantitative trait locus (QTL) analysis in both species, and the efficacy of the white clover map for this purpose was demonstrated with the initial identification of multiple QTL controlling seed yield and seedling vigour. One QTL on linkage group D2 accounts for 25.9% of the genetic variation for seed yield, and a putative QTL accounting for 12.7% of the genetic variation for seedling vigour was detected on linkage group E1. The application of MAS to forage breeding based on recurrent selection is discussed. Keywords: genome map, marker-assisted selection, perennial ryegrass, QTL, quantitative trait locus, SSR, simple sequence repeat, white clover

Can Crowdfunding Come to the Rescue of Culture and Arts? Evidence from Romania

2019 ◽  
Vol 3 (2) ◽  
pp. 73-82
Author(s):  
Mina Fanea-Ivanovici
Keyword(s):  
Success Rate ◽  
Public Financing ◽  
Artistic Creation ◽  
Cultural Activities ◽  
Convenient Tool ◽  
Cost Disease ◽  
Artistic Activity ◽  
To Receive

Financing culture and arts is a difficult task to achieve, especially due to the fact that the revenues ob-tained from such activities may not be enough to cover the costs. This has been claimed to be true for certain cultural activities or events, such as concerts, and is named Baumol’s cost disease. Although other forms of cultural and artistic activity can entirely rely upon the revenues earned, many types of artistic creation depend on public financing or sponsorship. With the advent and democratisation of Internet-based technologies, crowdfunding has become a convenient tool to raise funds in order to fi-nance cultural activities. The aim of this paper is to investigate to what extent cultural and artistic pro-jects are likely to receive financing through crowdfunding. The study is based on the main Romanian crowdfunding platforms and analyses the success rate of crowdfunding projects in culture and arts.

scholarly journals Secondary Trisomics and Telotrisomics of Rice: Origin, Characterization, and Use in Determining the Orientation of Chromosome Map

Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 517-529
Author(s):  
Kuldeep Singh ◽  
D S Multani ◽  
Gurdev S Khush
Keyword(s):  
Linkage Map ◽  
Large Population ◽  
Marker Genes ◽  
Linkage Groups ◽  
Breeding Behavior ◽  
Specific Chromosome ◽  
Chromosome Map ◽  
Primary Trisomics ◽  
Correct Orientation ◽  
Genetic Segregation

Abstract Secondary trisomics and telotrisomics representing the 12 chromosomes of rice were isolated from the progenies of primary trisomics. A large population of each primary trisomic was grown. Plants showing variation in gross morphology compared to the primary trisomics and disomic sibs were selected and analyzed cytologically at diakinesis and pachytene. Secondary trisomics for both arms of chromosomes 1, 2, 6, 7 and 11 and for one arm of chromosomes 4, 5, 8, 9 and 12 were identified. Telotrisomics for short arm of chromosomes 1, 8, 9 and 10 and for long arms of chromosomes 2, 3 and 5 were isolated. These secondary and telotrisomics were characterized morphologically and for breeding behavior. Secondary trisomics 2n + 1S · 1S, 2n + 1L · 1L, 2n + 2S · 2S, 2n + 2L · 2L, 2n + 6S · 6S, 2n + 6L · 6L and 2n + 7L · 7L are highly sterile, and 2n + 1L · 1L, 2n + 2L · 2L and 2n + 7L · 7L do not set any seed even upon backcrossing. Telotrisomics are fertile and vigorous. Genetic segregation of 43 marker genes was studied in the F2 or backcross progenies. On the basis of segregation data, these genes were delimited to specific chromosome arms. Correct orientation of 10 linkage groups was determined and centromere positions on nine linkage groups were approximated. A revised linkage map of rice is presented.

The Budding Yeast Msh4 Protein Functions in Chromosome Synapsis and the Regulation of Crossover Distribution

Genetics ◽  
2001 ◽  
Vol 158 (3) ◽  
pp. 1013-1025 ◽  
Author(s):  
Janet E Novak ◽  
Petra B Ross-Macdonald ◽  
G Shirleen Roeder
Keyword(s):  
Mismatch Repair ◽  
Budding Yeast ◽  
Null Mutation ◽  
Crossing Over ◽  
Wild Type ◽  
Crossover Interference ◽  
Meiotic Chromosomes ◽  
Chromosome Synapsis ◽  
Protein Functions ◽  
Or Gene

AbstractThe budding yeast MSH4 gene encodes a MutS homolog produced specifically in meiotic cells. Msh4 is not required for meiotic mismatch repair or gene conversion, but it is required for wild-type levels of crossing over. Here, we show that a msh4 null mutation substantially decreases crossover interference. With respect to the defect in interference and the level of crossing over, msh4 is similar to the zip1 mutant, which lacks a structural component of the synaptonemal complex (SC). Furthermore, epistasis tests indicate that msh4 and zip1 affect the same subset of meiotic crossovers. In the msh4 mutant, SC formation is delayed compared to wild type, and full synapsis is achieved in only about half of all nuclei. The simultaneous defects in synapsis and interference observed in msh4 (and also zip1 and ndj1/tam1) suggest a role for the SC in mediating interference. The Msh4 protein localizes to discrete foci on meiotic chromosomes and colocalizes with Zip2, a protein involved in the initiation of chromosome synapsis. Both Zip2 and Zip1 are required for the normal localization of Msh4 to chromosomes, raising the possibility that the zip1 and zip2 defects in crossing over are indirect, resulting from the failure to localize Msh4 properly.

scholarly journals Analysis and Mapping of Gene Families Encoding β-1,3-Glucanases of Soybean

Genetics ◽  
1999 ◽  
Vol 153 (1) ◽  
pp. 445-452
Author(s):  
Wei Jin ◽  
Harry T Horner ◽  
Reid G Palmer ◽  
Randy C Shoemaker
Keyword(s):  
Gene Families ◽  
Mrna Levels ◽  
Linkage Groups ◽  
Flower Bud ◽  
Cross Hybridization ◽  
Coding Regions ◽  
F2 Population ◽  
Young Leaves ◽  
Glycine Max L ◽  
Stem Leaf

Abstract Oligonucleotide primers designed for conserved sequences from coding regions of β-1,3-glucanase genes from different species were used to amplify related sequences from soybean [Glycine max (L.) Merr.]. Sequencing and cross-hybridization of amplification products indicated that at least 12 classes of β-1,3-glucanase genes exist in the soybean. Members of classes mapped to 34 loci on five different linkage groups using an F2 population of 56 individuals. β-1,3-Glucanase genes are clustered onto regions of five linkage groups. Data suggest that more closely related genes are clustered together on one linkage group or on duplicated regions of linkage groups. Northern blot analyses performed on total RNA from root, stem, leaf, pod, flower bud, and hypocotyl using DNA probes for the different classes of β-1,3-glucanase genes revealed that the mRNA levels of all classes were low in young leaves. SGlu2, SGlu4, SGlu7, and SGlu12 mRNA were highly accumulated in young roots and hypocotyls. SGlu7 mRNA also accumulated in pods and flower buds.

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