scholarly journals Sequence Composition and Evolution of Mammalian B Chromosomes

Genes ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 490 ◽  
Author(s):  
Nikolay Rubtsov ◽  
Yury Borisov
Keyword(s):  
Transcriptional Activity ◽  
Complex Analysis ◽  
B Chromosome ◽  
B Chromosomes ◽  
Intraspecific Diversity ◽  
Comparative Cytogenetics ◽  
Sequence Composition ◽  
Origin And Evolution ◽  
History Of ◽  
The Difference

B chromosomes (Bs) revealed more than a hundred years ago remain to be some of the most mysterious elements of the eukaryotic genome. Their origin and evolution, DNA composition, transcriptional activity, impact on adaptiveness, behavior in meiosis, and transfer to the next generation require intensive investigations using modern methods. Over the past years, new experimental techniques have been applied and helped us gain a deeper insight into the nature of Bs. Here, we consider mammalian Bs, taking into account data on their DNA sequencing, transcriptional activity, positions in nuclei of somatic and meiotic cells, and impact on genome functioning. Comparative cytogenetics of Bs suggests the existence of different mechanisms of their formation and evolution. Due to the long and complicated evolvement of Bs, the similarity of their morphology could be explained by the similar mechanisms involved in their development while the difference between Bs even of the same origin could appear due to their positioning at different stages of their evolution. A complex analysis of their DNA composition and other features is required to clarify the origin and evolutionary history of Bs in the species studied. The intraspecific diversity of Bs makes this analysis a very important element of B chromosome studies.

Identification of a family of repeated sequences on the rye B chromosome

Genome ◽  
1990 ◽  
Vol 33 (6) ◽  
pp. 908-913 ◽  
Author(s):  
Michael J. Sandery ◽  
John W. Forster ◽  
Richard Blunden ◽  
R. Neil Jones
Keyword(s):  
Secale Cereale ◽  
Direct Evidence ◽  
B Chromosome ◽  
Repeat Sequence ◽  
B Chromosomes ◽  
Repeated Sequences ◽  
Significant Heterogeneity ◽  
Origin And Evolution ◽  
The Family

A novel family of highly repeated sequences on the B chromosome of rye (Secale cereale) has been identified. The D1100 family has not been detected on the rye A chromosomes and shows little or no homology to any previously described repeat sequence in rye. In addition, different rye species, and different B chromosomes within the same species, show significant heterogeneity in the arrangement of the D1100 sequences. An EcoRI clone of a member of the family has been obtained. These results provide direct evidence for the organisation and nature of the B-chromosome DNA in rye, and they are discussed in relation to the origin and evolution of rye B chromosomes.Key words: B chromosome, Secale cereale, repeated sequences.

scholarly journals Satellite DNAs Unveil Clues about the Ancestry and Composition of B Chromosomes in Three Grasshopper Species

Genes ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 523 ◽  
Author(s):  
Diogo Milani ◽  
Vanessa Bardella ◽  
Ana Ferretti ◽  
Octavio Palacios-Gimenez ◽  
Adriana Melo ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescent In Situ Hybridization ◽  
B Chromosome ◽  
B Chromosomes ◽  
Satellite Dnas ◽  
Grasshopper Species ◽  
Repetitive Dnas ◽  
Origin And Evolution ◽  
Chromosomal Position

Supernumerary (B) chromosomes are dispensable genomic elements occurring frequently among grasshoppers. Most B chromosomes are enriched with repetitive DNAs, including satellite DNAs (satDNAs) that could be implicated in their evolution. Although studied in some species, the specific ancestry of B chromosomes is difficult to ascertain and it was determined in only a few examples. Here we used bioinformatics and cytogenetics to characterize the composition and putative ancestry of B chromosomes in three grasshopper species, Rhammatocerus brasiliensis, Schistocerca rubiginosa, and Xyleus discoideus angulatus. Using the RepeatExplorer pipeline we searched for the most abundant satDNAs in Illumina sequenced reads, and then we generated probes used in fluorescent in situ hybridization (FISH) to determine chromosomal position. We used this information to infer ancestry and the events that likely occurred at the origin of B chromosomes. We found twelve, nine, and eighteen satDNA families in the genomes of R. brasiliensis, S. rubiginosa, and X. d. angulatus, respectively. Some satDNAs revealed clustered organization on A and B chromosomes varying in number of sites and position along chromosomes. We did not find specific satDNA occurring in the B chromosome. The satDNAs shared among A and B chromosomes support the idea of putative intraspecific ancestry from small autosomes in the three species, i.e., pair S11 in R. brasiliensis, pair S9 in S. rubiginosa, and pair S10 in X. d. angulatus. The possibility of involvement of other chromosomal pairs in B chromosome origin is also hypothesized. Finally, we discussed particular aspects in composition, origin, and evolution of the B chromosome for each species.

scholarly journals Differential Expression of Genes Related to Sexual Determination Can Modify the Reproductive Cycle of Astyanax scabripinnis (Characiformes: Characidae) in B Chromosome Carrier Individuals

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 909 ◽  
Author(s):  
Jonathan Pena Castro ◽  
Ricardo Shohei Hattori ◽  
Túlio Teruo Yoshinaga ◽  
Duílio Mazzoni Zerbinato de Andrade Silva ◽  
Francisco J. Ruiz-Ruano ◽  
...  
Keyword(s):  
Differential Expression ◽  
Reproductive Cycle ◽  
Model Organism ◽  
B Chromosome ◽  
B Chromosomes ◽  
Astyanax Scabripinnis ◽  
Expression Of Genes ◽  
Sexual Determination ◽  
The Difference ◽  
Differential Expression Of Genes

The species complex Astyanax scabripinnis is one of the most studied with respect to origin, distribution, and frequency of B chromosomes, and is considered a model organism for evolutionary studies. Research using population inferences about the occurrence and frequency of the B chromosome shows seasonal variation between sexes, which is associated with the presence of this supernumerary element. We hypothesized that the B chromosome could influence the sex ratio of these animals. Based on this assumption, the present work aimed to investigate if differences exist among levels of gene expression with qRT-PCR of the amh (associated with testicular differentiation) and foxl2a (associated with ovarian differentiation) genes between B-carrier and non-B-carrier individuals. The results showed that for the amh gene, the difference in expression between animals with B chromosomes was not accentuated compared to that in animals without this chromosome. Expression of foxl2a in B-carrier females, however, was reduced by 73.56% compared to females that lacked the B chromosome. Males had no difference in expression of the amh and foxl2a genes between carriers and non-carriers of the B chromosome. Results indicate that the presence of B chromosomes is correlated with the differential expression of sex-associated genes. An analysis of these results integrated with data from other studies on the reproductive cycle in the same species reveals that this difference in expression may be expanding the reproductive cycle of the species.

Harsdörffers Geschirr

2019 ◽  
Vol 10 (1) ◽  
pp. 23-37
Author(s):  
Natalie Binczek
Keyword(s):  
Design History ◽  
History Of ◽  
The Difference

Der deutsche Barockdichter Georg Philipp Harsdörffer skizziert eine Theorie der Emblematik, die vor allem dessen Anwendungsvielfalt hervorhebt. Er hebt dabei besonders den Unterschied zwischen buchinterner und buchexterner Verwendung auf, indem er sich nicht nur für die Aufnahme der Embleme in Büchern, sondern auch auf Geschirr und Tapeten ausspricht. Der Beitrag liest Harsdörffers extensive Überlegungen nicht nur als Beiträge zur Theorie und Geschichte der Embleme als ›Sinn-Bilder‹, sondern auch als Beitrag zur Designgeschichte. German Baroque poet Georg Philipp Harsdörffer delineates a theory of emblematics that clearly sets itself apart from other contemporary theories, especially by its versatility. In particular, the author negates the difference between internal and external usage of emblems in books not only by promoting the incorporation of emblems into printed works but also by supporting their depiction on dishes and tapestries. This article strives to read Harsdörffer’s extensive thoughts on the matter of emblems not simply as another work on the theory and history of emblematics but rather as a contribution to design history as well

Introduction

2017 ◽  
Author(s):  
Simon Kirchin
Keyword(s):  
Hilary Putnam ◽  
Bernard Williams ◽  
General Methodology ◽  
Thick Concepts ◽  
History Of ◽  
Philippa Foot ◽  
The Difference

This chapter introduces the distinction between thin and thick concepts and then performs a number of functions. First, two major accounts of thick concepts—separationism and nonseparationism—are introduced and, in doing so, a novel account of evaluation is indicated. Second, each chapter is outlined as is the general methodology, followed, third, by a brief history of the discussion of thick concepts, referencing Philippa Foot, Hilary Putnam, Gilbert Ryle, and Bernard Williams among others. Fourth, a number of relevant contrasts are introduced, such as the fact–value distinction and the difference between concepts, properties, and terms. Lastly, some interesting and relevant questions are raised that, unfortunately, have to be left aside.

The Early History of Financial Economics, 1478–1776. By Geoffrey Poitras. Cheltenham and Northampton: Edward Elgar, 2000. Pp. x, 522.

2002 ◽  
Vol 62 (1) ◽  
pp. 268-269
Author(s):  
Larry Neal
Keyword(s):  
Economic History ◽  
Financial Analysis ◽  
Adam Smith ◽  
Economic Thought ◽  
Financial History ◽  
X 522 ◽  
History Of ◽  
The Difference ◽  
Wealth Of Nations ◽  
Simon Fraser University

Economic historians usually have to explain to their economist colleagues the difference between economic history, which focuses on facts, and history of economic thought, which focuses on ideas. Our colleagues in finance departments, typically fascinated by episodes in financial history treated by economic historians, are bound to be disappointed in the lack of attention given to the development of ideas in finance by historians of economic thought. Geoffrey Poitras, a professor of finance at Simon Fraser University, makes a valiant effort to remedy these oversights in his collection of vignettes that highlight the sophistication of financial instruments and analysts of financial markets well before the time of Adam Smith. Starting in 1478 with the publication of the Treviso Arithmetic, a typical textbook of commercial arithmetic for Italian merchants, and ending with brief snippets from the Wealth of Nations, Poitras treats the reader to a fascinating potpourri of excerpts from various manuals, brief biographies of pioneers in financial analysis, and historical discursions on foreign-exchange and stock markets.

scholarly journals Reproducibility and Instruction Following in the Shop Floor Laboratory Work: The Case of a TMS Experiment

2021 ◽  
pp. 016224392110323
Author(s):  
Kristina Popova
Keyword(s):  
Measurement Procedure ◽  
Shop Floor ◽  
Experimental Uncertainty ◽  
Local Measurement ◽  
Replication Crisis ◽  
History Of ◽  
Per Se ◽  
The Difference ◽  
Methodological Guidelines ◽  
Local Procedure

The article addresses the production of reproducibility as a topic that has become acutely relevant in the recent discussions on the replication crisis in science. It brings the ethnomethodological stance on reproducibility into the discussions, claiming that reproducibility is necessarily produced locally, on the shop floor, with methodological guidelines serving as references to already established practices rather than their origins. The article refers to this argument empirically, analyzing how a group of novice neuroscientists performs a series of measurements in a transcranial magnetic stimulation experiment. Based on ethnography and video analysis, the article traces a history of the local measurement procedure invented by the researchers in order to overcome the experimental uncertainty. The article aims to demonstrate (1) how reproducibility of the local procedure is achieved in the shop floor work of the practitioners and (2) how the procedure becomes normalized and questioned as incorrect in the course of experimental practice. It concludes that the difference between guidelines and practical actions is not problematic per se; what may be problematic is that researchers can be engaged in different working projects described by the same instruction.

Incidence of postural headache after lumbar puncture requiring epidural blood patch: Effects of needle caliber; 2-year experience

2021 ◽  
pp. 197140092110006
Author(s):  
Warren Chang ◽  
Ajla Kadribegic ◽  
Kate Denham ◽  
Matthew Kulzer ◽  
Tyson Tragon ◽  
...  
Keyword(s):  
Risk Factors ◽  
Lumbar Puncture ◽  
Conservative Management ◽  
Epidural Blood Patch ◽  
Female Gender ◽  
Regional Hospital ◽  
Younger Age ◽  
Blood Patch ◽  
History Of ◽  
The Difference

Purpose A common complication of lumbar puncture (LP) is postural headaches. Epidural blood patches are recommended if patients fail conservative management. Owing to a perceived increase in the number of post-lumbar puncture headaches (PLPHs) requiring epidural blood patches at a regional hospital in our network, the decision was made to switch from 20 to 22 gauge needles for routine diagnostic LPs. Materials and methods Patients presenting for LP and myelography at one network regional hospital were included in the study. The patients were contacted by nursing staff 3 days post-procedure; those patients who still had postural headaches after conservative management and received epidural blood patches were considered positive cases. In total, 292 patients were included; 134 underwent LP with 20-gauge needles (53 male, 81 female, average age 57.7) and 158 underwent LP with 22-gauge needles (79 male, 79 female, average age 54.6). Results Of 134 patients undergoing LP with 20-gauge needles, 15 (11%) had PLPH requiring epidural blood patch (11 female, 3 male, average age 38). Of 158 patients undergoing LP with 22-gauge needles, only 5 (3%) required epidural blood patches (all female, average age 43). The difference was statistically significant ( p < 0.01). Risk factors for PLPH included female gender, younger age, lower body mass index, history of prior PLPH and history of headaches. Conclusion Switching from 20-gauge to 22-gauge needles significantly decreased the incidence of PLPH requiring epidural blood patch. Narrower gauge or non-cutting needles should be considered in patients with risk factors for PLPH, allowing for CSF requirements.

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