scholarly journals How Can Satellite DNA Divergence Cause Reproductive Isolation? Let Us Count the Chromosomal Ways

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Patrick M. Ferree ◽  
Satyaki Prasad
Keyword(s):  
Reproductive Isolation ◽  
Developmental Stages ◽  
Rapid Evolution ◽  
Model Organisms ◽  
Cellular Mechanisms ◽  
Closely Related Species ◽  
Heterochromatin Formation ◽  
Interspecies Hybrids ◽  
Postzygotic Reproductive Isolation ◽  
And Function

Satellites are one of the most enigmatic parts of the eukaryotic genome. These highly repetitive, noncoding sequences make up as much as half or more of the genomic content and are known to play essential roles in chromosome segregation during meiosis and mitosis, yet they evolve rapidly between closely related species. Research over the last several decades has revealed that satellite divergence can serve as a formidable reproductive barrier between sibling species. Here we highlight several key studies on Drosophila and other model organisms demonstrating deleterious effects of satellites and their rapid evolution on the structure and function of chromosomes in interspecies hybrids. These studies demonstrate that satellites can impact chromosomes at a number of different developmental stages and through distinct cellular mechanisms, including heterochromatin formation. These findings have important implications for how loci that cause postzygotic reproductive isolation are viewed.

scholarly journals Inter-species comparison of the orientation algorithm directing larval chemotaxis in the genus Drosophila

2021 ◽  
Author(s):  
Elie Fink ◽  
Matthieu Louis
Keyword(s):  
Neural Circuits ◽  
Rapid Evolution ◽  
Structure And Function ◽  
Olfactory Behavior ◽  
Species Comparison ◽  
Closely Related Species ◽  
Genetic Studies ◽  
Phenotypic Differences ◽  
Peripheral Olfactory System ◽  
And Function

Animals differ in their appearances and behaviors. While many genetic studies have addressed the origins of phenotypic differences between fly species, we are still lacking a quantitative assessment of the variability in the way different fly species behave. We tackled this question in one of the most robust behaviors displayed by Drosophila: chemotaxis. At the larval stage, Drosophila melanogaster navigate odor gradients by combining four sensorimotor routines in a multilayered algorithm: a modulation of the overall locomotor speed and turn rate; a bias in turning during down-gradient motion; a bias in turning toward the gradient; the local curl of trajectories toward the gradient ("weathervaning"). Using high-resolution tracking and behavioral quantification, we characterized the olfactory behavior of eight closely related species of the Drosophila group in response to 19 ecologically-relevant odors. Significant changes are observed in the receptive field of each species, which is consistent with the rapid evolution of the peripheral olfactory system. Our results reveal substantial inter-species variability in the algorithms directing larval chemotaxis. While the basic sensorimotor routines are shared, their parametric arrangements can vary dramatically across species. The present analysis sets the stage for deciphering the evolutionary relationships between the structure and function of neural circuits directing orientation behaviors in Drosophila.

scholarly journals Limited intrinsic postzygotic reproductive isolation despite chromosomal rearrangements between closely related sympatric species of small ermine moths (Lepidoptera: Yponomeutidae)

2019 ◽  
Vol 128 (1) ◽  
pp. 44-58 ◽  
Author(s):  
Katerina H Hora ◽  
František Marec ◽  
Peter Roessingh ◽  
Steph B J Menken
Keyword(s):  
Reproductive Isolation ◽  
Parental Species ◽  
Meiotic Chromosome ◽  
Chromosomal Rearrangements ◽  
Sympatric Species ◽  
Hybrid Fitness ◽  
New Host ◽  
Closely Related Species ◽  
Postzygotic Reproductive Isolation

Abstract In evolutionarily young species and sympatric host races of phytophagous insects, postzygotic incompatibility is often not yet fully developed, but reduced fitness of hybrids is thought to facilitate further divergence. However, empirical evidence supporting this hypothesis is limited. To assess the role of reduced hybrid fitness, we studied meiosis and fertility in hybrids of two closely related small ermine moths, Yponomeuta padella and Yponomeuta cagnagella, and determined the extent of intrinsic postzygotic reproductive isolation. We found extensive rearrangements between the karyotypes of the two species and irregularities in meiotic chromosome pairing in their hybrids. The fertility of reciprocal F1 and, surprisingly, also of backcrosses with both parental species was not significantly decreased compared with intraspecific offspring. The results indicate that intrinsic postzygotic reproductive isolation between these closely related species is limited. We conclude that the observed chromosomal rearrangements are probably not the result of an accumulation of postzygotic incompatibilities preventing hybridization. Alternative explanations, such as adaptation to new host plants, are discussed.

RAPID EVOLUTION OF POSTZYGOTIC REPRODUCTIVE ISOLATION IN STALK-EYED FLIES

Evolution ◽  
2005 ◽  
Vol 59 (4) ◽  
pp. 849 ◽  
Author(s):  
Sarah J. Christianson ◽  
John G. Swallow ◽  
Gerald S. Wilkinson
Keyword(s):  
Reproductive Isolation ◽  
Rapid Evolution ◽  
Postzygotic Reproductive Isolation

scholarly journals Radical remodeling of the Y chromosome in a recent radiation of malaria mosquitoes

2016 ◽  
Vol 113 (15) ◽  
pp. E2114-E2123 ◽  
Author(s):  
Andrew Brantley Hall ◽  
Philippos-Aris Papathanos ◽  
Atashi Sharma ◽  
Changde Cheng ◽  
Omar S. Akbari ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Single Molecule ◽  
Developmental Stages ◽  
Mosquito Control ◽  
Control Strategies ◽  
Sequence Similarity ◽  
Rapid Evolution ◽  
Model Organisms ◽  
Malaria Vectors ◽  
Y Chromosomes

Y chromosomes control essential male functions in many species, including sex determination and fertility. However, because of obstacles posed by repeat-rich heterochromatin, knowledge of Y chromosome sequences is limited to a handful of model organisms, constraining our understanding of Y biology across the tree of life. Here, we leverage long single-molecule sequencing to determine the content and structure of the nonrecombining Y chromosome of the primary African malaria mosquito, Anopheles gambiae. We find that the An. gambiae Y consists almost entirely of a few massively amplified, tandemly arrayed repeats, some of which can recombine with similar repeats on the X chromosome. Sex-specific genome resequencing in a recent species radiation, the An. gambiae complex, revealed rapid sequence turnover within An. gambiae and among species. Exploiting 52 sex-specific An. gambiae RNA-Seq datasets representing all developmental stages, we identified a small repertoire of Y-linked genes that lack X gametologs and are not Y-linked in any other species except An. gambiae, with the notable exception of YG2, a candidate male-determining gene. YG2 is the only gene conserved and exclusive to the Y in all species examined, yet sequence similarity to YG2 is not detectable in the genome of a more distant mosquito relative, suggesting rapid evolution of Y chromosome genes in this highly dynamic genus of malaria vectors. The extensive characterization of the An. gambiae Y provides a long-awaited foundation for studying male mosquito biology, and will inform novel mosquito control strategies based on the manipulation of Y chromosomes.

scholarly journals Proteins of penial mamilliform glands in closely related Littorina species (Mollusca, Caenogastropoda): variability and possible contribution to reproductive isolation

2020 ◽  
Vol 65 (2) ◽  
Author(s):  
Arseniy Lobov ◽  
Irina Babkina ◽  
Arina Maltseva ◽  
Natalia Mikhailova ◽  
Andrey Granovitch
Keyword(s):  
Reproductive Isolation ◽  
Related Species ◽  
Sympatric Speciation ◽  
Central Place ◽  
Model Organisms ◽  
Reproductive Barriers ◽  
Closely Related Species ◽  
Comparative Proteomic Analysis ◽  
Specific Proteins ◽  
Species Specific

The forces driving reproductive isolation emergence during the process of sympatric speciation are still intensely debated. Mechanisms of gametic isolation (which are known to form rapidly in several models) take the central place in these debates. Nevertheless, the approximative capacity of a few investigated models to other taxa could be questioned, generating demand for the adoption of additional model organisms to study sympatric speciation. The group of closely related species of the genus Littorina (subgenus Neritrema) sympatrically inhabiting seashores are promising. In this study, we performed comparative proteomic analysis of penial tissues of four Neritrema species to identify potential effectors contributing to gametic isolation. Among 272 analyzed proteins, 13 mamilliform gland-specific proteins (possibly transferred to the female during copulation) were detected, as well as five proteins specifically expressed in the epithelium of the penial basal part. Eight of these proteins were species-specific and may be involved in the maintenance of reproductive barriers.

The Evolutionary Analysis of “Orphans” From the Drosophila Genome Identifies Rapidly Diverging and Incorrectly Annotated Genes

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 589-598 ◽  
Author(s):  
Karl J Schmid ◽  
Charles F Aquadro
Keyword(s):  
Related Species ◽  
Rapid Evolution ◽  
Model Organisms ◽  
Drosophila Genome ◽  
Evolutionary Analysis ◽  
Orphan Genes ◽  
Closely Related Species ◽  
Reading Frame ◽  
Nearly Neutral Mutations ◽  
Neutral Mutations

Abstract In genome projects of eukaryotic model organisms, a large number of novel genes of unknown function and evolutionary history (“orphans”) are being identified. Since many orphans have no known homologs in distant species, it is unclear whether they are restricted to certain taxa or evolve rapidly, either because of a lack of constraints or positive Darwinian selection. Here we use three criteria for the selection of putatively rapidly evolving genes from a single sequence of Drosophila melanogaster. Thirteen candidate genes were chosen from the Adh region on the second chromosome and 1 from the tip of the X chromosome. We succeeded in obtaining sequence from 6 of these in the closely related species D. simulans and D. yakuba. Only 1 of the 6 genes showed a large number of amino acid replacements and in-frame insertions/deletions. A population survey of this gene suggests that its rapid evolution is due to the fixation of many neutral or nearly neutral mutations. Two other genes showed “normal” levels of divergence between species. Four genes had insertions/deletions that destroy the putative reading frame within exons, suggesting that these exons have been incorrectly annotated. The evolutionary analysis of orphan genes in closely related species is useful for the identification of both rapidly evolving and incorrectly annotated genes.

scholarly journals Altered Localization of Hybrid Incompatibility Proteins in Drosophila

2019 ◽  
Vol 36 (8) ◽  
pp. 1783-1792 ◽  
Author(s):  
Jacob Carter Cooper ◽  
Andrea Lukacs ◽  
Shelley Reich ◽  
Tamas Schauer ◽  
Axel Imhof ◽  
...  
Keyword(s):  
Molecular Interaction ◽  
Binding Sites ◽  
Protein Localization ◽  
Rapid Evolution ◽  
Evolutionary Genetics ◽  
Hybrid Male ◽  
Hybrid Incompatibility ◽  
Interspecies Hybrids ◽  
Single Complex ◽  
And Function

Abstract Understanding the molecular basis of hybrid incompatibilities is a fundamental pursuit in evolutionary genetics. In crosses between Drosophila melanogaster females and Drosophila simulans males, an interaction between at least three genes is necessary for hybrid male lethality: Hmr mel, Lhr sim, and gfzf sim. Although HMR and LHR physically bind each other and function together in a single complex, the connection between gfzf and either of these proteins remains mysterious. Here, we show that GFZF localizes to many regions of the genome in both D. melanogaster and D. simulans, including at telomeric retrotransposon repeats. We find that GFZF localization at telomeres is significantly different between these two species, reflecting the rapid evolution of telomeric retrotransposon copy number composition between the two species. Next, we show that GFZF and HMR normally do not colocalize in D. melanogaster. In interspecies hybrids, however, HMR shows extensive mis-localization to GFZF sites, thus uncovering a new molecular interaction between these hybrid incompatibility factors. We find that spreading of HMR to GFZF sites requires gfzf sim but not Lhr sim, suggesting distinct roles for these factors in the hybrid incompatibility. Finally, we find that overexpression of HMR and LHR within species is sufficient to mis-localize HMR to GFZF binding sites, indicating that HMR has a natural low affinity for GFZF sites. Together, these studies provide the first insights into the different properties of gfzf between D. melanogaster and D. simulans, and uncover a molecular interaction between gfzf and Hmr in the form of altered protein localization.

scholarly journals Significance of Mast Cell Formed Extracellular Traps in Microbial Defense

2021 ◽  
Author(s):  
Daniel Elieh Ali Komi ◽  
Wolfgang M. Kuebler
Keyword(s):  
State Of The Art ◽  
Extracellular Dna ◽  
Cellular Mechanisms ◽  
Extracellular Traps ◽  
Synthetic Chemicals ◽  
Dna Strands ◽  
Associated Proteins ◽  
Microbial Defense ◽  
And Function ◽  
Insight Into

AbstractMast cells (MCs) are critically involved in microbial defense by releasing antimicrobial peptides (such as cathelicidin LL-37 and defensins) and phagocytosis of microbes. In past years, it has become evident that in addition MCs may eliminate invading pathogens by ejection of web-like structures of DNA strands embedded with proteins known together as extracellular traps (ETs). Upon stimulation of resting MCs with various microorganisms, their products (including superantigens and toxins), or synthetic chemicals, MCs become activated and enter into a multistage process that includes disintegration of the nuclear membrane, release of chromatin into the cytoplasm, adhesion of cytoplasmic granules on the emerging DNA web, and ejection of the complex into the extracellular space. This so-called ETosis is often associated with cell death of the producing MC, and the type of stimulus potentially determines the ratio of surviving vs. killed MCs. Comparison of different microorganisms with specific elimination characteristics such as S pyogenes (eliminated by MCs only through extracellular mechanisms), S aureus (removed by phagocytosis), fungi, and parasites has revealed important aspects of MC extracellular trap (MCET) biology. Molecular studies identified that the formation of MCET depends on NADPH oxidase-generated reactive oxygen species (ROS). In this review, we summarize the present state-of-the-art on the biological relevance of MCETosis, and its underlying molecular and cellular mechanisms. We also provide an overview over the techniques used to study the structure and function of MCETs, including electron microscopy and fluorescence microscopy using specific monoclonal antibodies (mAbs) to detect MCET-associated proteins such as tryptase and histones, and cell-impermeant DNA dyes for labeling of extracellular DNA. Comparing the type and biofunction of further MCET decorating proteins with ETs produced by other immune cells may help provide a better insight into MCET biology in the pathogenesis of autoimmune and inflammatory disorders as well as microbial defense.

scholarly journals Molecular and phenotypic analysis of rodent models reveals conserved and species-specific modulators of human sarcopenia

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Anastasiya Börsch ◽  
Daniel J. Ham ◽  
Nitish Mittal ◽  
Lionel A. Tintignac ◽  
Eugenia Migliavacca ◽  
...  
Keyword(s):  
Muscle Mass ◽  
Inflammatory Responses ◽  
Molecular Data ◽  
Model Organisms ◽  
Sequencing Data ◽  
Phenotypic Analysis ◽  
Age Related ◽  
Analogous Data ◽  
Species Specific ◽  
And Function

AbstractSarcopenia, the age-related loss of skeletal muscle mass and function, affects 5–13% of individuals aged over 60 years. While rodents are widely-used model organisms, which aspects of sarcopenia are recapitulated in different animal models is unknown. Here we generated a time series of phenotypic measurements and RNA sequencing data in mouse gastrocnemius muscle and analyzed them alongside analogous data from rats and humans. We found that rodents recapitulate mitochondrial changes observed in human sarcopenia, while inflammatory responses are conserved at pathway but not gene level. Perturbations in the extracellular matrix are shared by rats, while mice recapitulate changes in RNA processing and autophagy. We inferred transcription regulators of early and late transcriptome changes, which could be targeted therapeutically. Our study demonstrates that phenotypic measurements, such as muscle mass, are better indicators of muscle health than chronological age and should be considered when analyzing aging-related molecular data.

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