scholarly journals Chromosomal phylogeny of Robertsonian races of the house mouse on the island of Madeira: testing between alternative mutational processes

2005 ◽  
Vol 86 (3) ◽  
pp. 171-183 ◽  
Author(s):  
JANICE BRITTON-DAVIDIAN ◽  
JOSETTE CATALAN ◽  
MARIA DA GRAÇA RAMALHINHO ◽  
JEAN-CHRISTOPHE AUFFRAY ◽  
ANA CLAUDIA NUNES ◽  
...  
Keyword(s):  
House Mouse ◽  
Single Event ◽  
Reciprocal Translocations ◽  
Chromosomal Races ◽  
Chromosomal Change ◽  
Branch Support ◽  
Acrocentric Chromosomes ◽  
Mutational Processes ◽  
Chromosomal Phylogeny

The ancestral karyotype of the house mouse (Mus musculus) consists of 40 acrocentric chromosomes, but numerous races exist within the domesticus subspecies characterized by different metacentric chromosomes formed by the joining at the centromere of two acrocentrics. An exemplary case is present on the island of Madeira where six highly divergent chromosomal races have accumulated different combinations of 20 metacentrics in 500–1000 years. Chromosomal cladistic phylogenies were performed to test the relative performance of Robertsonian (Rb) fusions, Rb fissions and whole-arm reciprocal translocations (WARTs) in resolving relationships between the chromosomal races. The different trees yielded roughly similar topologies, but varied in the number of steps and branch support. The analyses using Rb fusions/fissions as characters resulted in poorly supported trees requiring six to eight homoplasious events. Allowance for WARTs considerably increased nodal support and yielded the most parsimonious trees since homoplasy was reduced to a single event. The WART-based trees required five to nine WARTs and 12 to 16 Rb fusions. These analyses provide support for the role of WARTs in generating the extensive chromosomal diversification observed in house mice. The repeated occurrence of Rb fusions and WARTs highlights the contribution of centromere-related rearrangements to accelerated rates of chromosomal change in the house mouse.

Role of Elastic Scattering of Protons, Muons, and Electrons in Inducing Single-Event Upsets

2017 ◽  
Vol 64 (10) ◽  
pp. 2648-2660 ◽  
Author(s):  
Avraham Akkerman ◽  
Joseph Barak ◽  
Nir M. Yitzhak
Keyword(s):  
Elastic Scattering ◽  
Single Event ◽  
Single Event Upsets

scholarly journals Accessibility Over Transposable Elements Reveals Genetic Determinants of Stemness Properties in Normal and Leukemic Hematopoiesis

2021 ◽  
Author(s):  
Bettina Nadorp ◽  
Giacomo Grillo ◽  
Aditi Qamra ◽  
Amanda Mitchell ◽  
Christopher Arlidge ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Chromatin Accessibility ◽  
Genetic Determinants ◽  
Hematopoietic Stem ◽  
Transcription Regulators ◽  
Docking Sites ◽  
Cellular Hierarchy ◽  
Mutational Processes

AbstractDespite most acute myeloid leukemia (AML) patients achieving complete remission after induction chemotherapy, two thirds of patients will relapse with fatal disease within 5 years. AML is organized as a cellular hierarchy sustained by leukemia stem cells (LSC) at the apex, with LSC properties directly linked to tumor progression, therapy failure and disease relapse 1–5. Despite the central role of LSC in poor patient outcomes, little is known of the genetic determinants of their stemness properties 6–8. Although much AML research focuses on mutational processes and their impact on gene expression programs, the genetic determinants of cell state properties including stemness expand beyond mutations, relying on the genetic architecture captured in the chromatin of each cell 9–11. As LSCs share many functional and molecular properties with normal hematopoietic stem cells (HSC), we identified genetic determinants of primitive populations enriched for LSCs and HSCs in comparison with their downstream mature progeny by investigating their chromatin accessibility. Our work reveals how distinct transposable element (TE) subfamilies are used in primitive versus mature populations, functioning as docking sites for stem cell-associated regulators of genome topology, including CTCF, or lineage-specific transcription regulators in primitive and mature populations, respectively. We further show how TE subfamilies accessible in LSCs define docking sites for several oncogenic drivers in AML, namely FLI1, LYL1 and MEIS1. Using chromatin accessibility profiles from a cohort of AML patients, we further show the clinical utility of our TE accessibility-based LSCTE121 scoring scheme to identify patients with high rates of relapse. Collectively, our work reveals how different accessible TE subfamilies serve as genetic determinants of stemness properties in normal and leukemic hematopoietic stem cells.

scholarly journals The role of copy-number variation in the reinforcement of sexual isolation between the two European subspecies of the house mouse

2020 ◽  
Vol 375 (1806) ◽  
pp. 20190540 ◽  
Author(s):  
Henry L. North ◽  
Pierre Caminade ◽  
Dany Severac ◽  
Khalid Belkhir ◽  
Carole M. Smadja
Keyword(s):  
Mate Choice ◽  
Copy Number Variation ◽  
Reproductive Isolation ◽  
House Mouse ◽  
Copy Number ◽  
Structural Changes ◽  
Sexual Isolation ◽  
Number Variation ◽  
Tandem Duplications

Reinforcement has the potential to generate strong reproductive isolation through the evolution of barrier traits as a response to selection against maladaptive hybridization, but the genetic changes associated with this process remain largely unexplored. Building upon the increasing evidence for a role of structural variants in adaptation and speciation, we addressed the role of copy-number variation in the reinforcement of sexual isolation evidenced between the two European subspecies of the house mouse. We characterized copy-number divergence between populations of Mus musculus musculus that display assortative mate choice, and those that do not, using whole-genome resequencing data. Updating methods to detect deletions and tandem duplications (collectively: copy-number variants, CNVs) in Pool-Seq data, we developed an analytical pipeline dedicated to identifying genomic regions showing the expected pattern of copy-number displacement under a reinforcement scenario. This strategy allowed us to detect 1824 deletions and seven tandem duplications that showed extreme differences in frequency between behavioural classes across replicate comparisons. A subset of 480 deletions and four tandem duplications were specifically associated with the derived trait of assortative mate choice. These ‘Choosiness-associated’ CNVs occur in hundreds of genes. Consistent with our hypothesis, such genes included olfactory receptors potentially involved in the olfactory-based assortative mate choice in this system as well as one gene, Sp110 , that is known to show patterns of differential expression between behavioural classes in an organ used in mate choice—the vomeronasal organ. These results demonstrate that fine-scale structural changes are common and highly variable within species, despite being under-studied, and may be important targets of reinforcing selection in this system and others. This article is part of the theme issue ‘Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers’.

scholarly journals Genic differentiation and origin of Robertsonian populations of the house mouse (Mus musculus domesticus Rutty)

1989 ◽  
Vol 53 (1) ◽  
pp. 29-44 ◽  
Author(s):  
Janice Britton-Davidian ◽  
Joseph H. Nadeau ◽  
Henri Croset ◽  
Louis Thaler
Keyword(s):  
Gene Flow ◽  
House Mouse ◽  
Mus Musculus ◽  
Western Europe ◽  
Chromosomal Rearrangements ◽  
Nuclear Gene ◽  
Electrophoretic Analysis ◽  
Mus Musculus Domesticus ◽  
Effective Population ◽  
Chromosomal Races

SummaryThis paper examines the relation between chromosomal and nuclear-gene divergence in 28 wild populations of the house mouse semi-species, Mus musculus domesticus, in Western Europe and North Africa. Besides describing the karyotypes of 15 of these populations and comparing them to those of 13 populations for which such information was already known, it reports the results of an electrophoretic survey of proteins encoded by 34 nuclear loci in all 28 populations. Karyotypic variation in this taxon involves only centric (or Robertsonian) fusions which often differ in arm combination and number between chromosomal races. The electrophoretic analysis showed that the amount of genic variation within Robertsonian (Rb) populations was similar to that for all-acrocentric populations, i.e. bearing the standard karyotype. Moreover, divergence between the two types of populations was extremely low. These results imply that centric fusions in mice have not modified either the level or the nature of genic variability. The genetic similarity between Rb and all-acrocentric populations is not attributed to the persistence of gene flow, since multiple fusions cause marked reproductive isolation. Rather, we attribute this extreme similarity to the very recent origin of chromosomal races in Europe. Furthermore, genic diversity measures suggest that geographically separated Rb populations have in situ and independent origins. Thus, Rb translocations are probably not unique events, but originated repeatedly. Two models are presented to explain how the rapid fixation of a series of chromosomal rearrangements can occur in a population without lowering variability in the nuclear genes. The first model assumes that chromosomal mutation rates are between 10−3 and 10−4 and that populations underwent a series of transient bottlenecks in which the effective population size did not fall below 35. In the second model, genic variability is restored following severe bottlenecks, through gene flow and recombination.

scholarly journals On the Attribution of a Single Event to Climate Change

2014 ◽  
Vol 27 (22) ◽  
pp. 8297-8301 ◽  
Author(s):  
Gerrit Hansen ◽  
Maximilian Auffhammer ◽  
Andrew R. Solow
Keyword(s):  
Climate Change ◽  
Confidence Interval ◽  
Recent Work ◽  
Extreme Weather ◽  
Historical Record ◽  
Attributable Risk ◽  
Extreme Weather Events ◽  
Single Event ◽  
Weather Events

Abstract There is growing interest in assessing the role of climate change in observed extreme weather events. Recent work in this area has focused on estimating a measure called attributable risk. A statistical formulation of this problem is described and used to construct a confidence interval for attributable risk. The resulting confidence is shown to be surprisingly wide even in the case where the event of interest is unprecedented in the historical record.

scholarly journals KARYOTYPIC ANALYSIS OF CHROMOSOMAL POLYMORPHISM IN RELATION TO REPRODUCTIVE FAILURE

2017 ◽  
Vol 9 (4) ◽  
pp. 140
Author(s):  
Ketan K. Vaghasia ◽  
Nidhi D. Shah ◽  
Parth S. Shah ◽  
Vidhi M. Bhatt ◽  
Sandip C. Shah ◽  
...  
Keyword(s):  
Genetic Counseling ◽  
Cytogenetic Analysis ◽  
Reproductive Function ◽  
Chromosomal Polymorphism ◽  
Giemsa Staining ◽  
Karyotypic Analysis ◽  
Blood Samples ◽  
Molecular Studies ◽  
Acrocentric Chromosomes

Objective: This study was undertaken to elucidate the role of heteromorphism in causation of reproductive anomalies like infertility.Methods: In our study, cytogenetic analysis of 830 suspected referral cases of both sexes were assessed using standard karyotypic technique with Giemsa staining from their blood samples. We identified heteromorphism of D/G groups and non-acrocentric chromosomes following WHO nomenclature.Results: Our data revealed that most of our heteromorphic cases (38;4.58%) were related to p arm satellites (ps+) of the chromosomes and are related to infertility and abortion. No significant gender variation was noticed in this study.Conclusion: We hence, suggest that heteromorphism is associated with a loss of reproductive function, as heterochromatin may contain genes that regulate cellular roles in reproduction. Further, it becomes important that such cases are considered for molecular studies, genetic counseling and prenatal/pre-implantation screening.

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