scholarly journals Shedding light on the grey zone of speciation along a continuum of genomic divergence

2016 ◽  
Author(s):  
Camille Roux ◽  
Christelle Fraïsse ◽  
Jonathan Romiguier ◽  
Yoann Anciaux ◽  
Nicolas Galtier ◽  
...  
Keyword(s):  
Gene Flow ◽  
Gene Pools ◽  
Grey Zone ◽  
Gradual Process ◽  
Genomic Divergence ◽  
High Incidence ◽  
The Status ◽  
Approximate Bayesian ◽  
Progressive Accumulation ◽  
The Continuum

AbstractSpeciation results from the progressive accumulation of mutations that decrease the probability of mating between parental populations, or reduce the fitness of hybrids - the so-called species barriers. The speciation genomic literature, however, is mainly a collection of case studies, each with its own approach and specificities, such that a global view of the gradual process of evolution from one to two species is currently lacking. Of primary importance is the prevalence of gene flow between diverging entities, which is central in most species concepts, and has been widely discussed in recent years. Here we explore the continuum of speciation thanks to a comparative analysis of genomic data from 61 pairs of populations/species of animals with variable levels of divergence. Gene flow between diverging gene pools is assessed under an Approximate Bayesian Computation (ABC) framework. We show that the intermediate "grey zone" of speciation, in which taxonomy is often controversial, spans from 0.5% to 2% of net synonymous divergence, irrespective of species life-history traits or ecology. Thanks to appropriate modeling of among-loci variation in genetic drift and introgression rate, we clarify the status of the majority of ambiguous cases and uncover a number of cryptic species. Our analysis also reveals the high incidence in animals of semi-isolated species, when some but not all loci are affected by barriers to gene flow, and highlights the intrinsic difficulty, both statistical and conceptual, of delineating species in the grey zone of speciation.

Clinical characteristics of patients with reproductive dysfunction and benign ovarian neoplasms

2021 ◽  
Vol 50 (4) ◽  
pp. 38-42
Author(s):  
R. G. Gataulina
Keyword(s):  
Incidence Rate ◽  
Clinical Characteristics ◽  
Ovarian Neoplasms ◽  
Reproductive Function ◽  
Research Center ◽  
Medical Sciences ◽  
Reproductive Disorders ◽  
High Incidence ◽  
The Status ◽  
High Incidence Rate

The study reports on the analysis of the anamnestic data of2044 women with reproductive disorders who underwent operative interventions for tumors and tumorlike masses of the ovaries during the period of 1989-1999 in the Research Center of Obstetrics, Gynecology and Perinatology of the Russian Academy of Medical Sciences. A high incidence rate о f complicated anamnesis and the coexisting somatic and extragenital diseases was revealed. The data are presented concerning the status of menstrual and reproductive function of the patients examined.

Continuity and Intuition in Eighteenth-Century Analysis and in Kant

2020 ◽  
pp. 158-186
Author(s):  
Daniel Sutherland
Keyword(s):  
Eighteenth Century ◽  
18Th Century ◽  
The Status ◽  
History Of ◽  
History Of Analysis ◽  
The Continuum ◽  
Interesting Account ◽  
The Way

This chapter considers the status of geometrical and kinematic representations in the foundations of 18th century analysis and in Kant’s understanding of those foundations. It has two aims. First, relying on relatively recent reassessments of the history of analysis, it will attempt to bring forward a more accurate account of intuitive representation in 18th century analysis and the relation between British and Continental mathematics. Second, it will give a better account of Kant’s place in that history. The result shows that although Kant did no better at navigating the labyrinth of the continuum than his contemporaries, he had a more interesting and reasonable account of the foundations of analysis than an easy reading of either Kant or that history provides. It also permits a more accurate and interesting account of how and when a conception of foundations of analysis without intuitive representations emerged, and how that paved the way for Bolzano and Cauchy.

scholarly journals Leptonic Decays of Heavy Quarks on the Lattice

1997 ◽  
Vol 12 (25) ◽  
pp. 4477-4538 ◽  
Author(s):  
Hartmut Wittig
Keyword(s):  
Cp Violation ◽  
Continuum Limit ◽  
Systematic Errors ◽  
Decay Constants ◽  
Leptonic Decays ◽  
The Standard Model ◽  
Lattice Calculations ◽  
The Status ◽  
Lattice Approach ◽  
The Continuum

The status of lattice calculations of heavy-light decay constants and of the B parameter BB is reviewed. After describing the lattice approach to heavy quark systems, the main results are discussed, with special emphasis on the systematic errors in present lattice calculations. A detailed analysis of the continuum limit for decay constants is performed. The implications of lattice results on studies of CP violation in the Standard Model are discussed.

scholarly journals Contrasting signatures of genomic divergence during sympatric speciation

Nature ◽  
2020 ◽  
Vol 588 (7836) ◽  
pp. 106-111 ◽  
Author(s):  
Andreas F. Kautt ◽  
Claudius F. Kratochwil ◽  
Alexander Nater ◽  
Gonzalo Machado-Schiaffino ◽  
Melisa Olave ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Architecture ◽  
Single Species ◽  
Sympatric Speciation ◽  
Ecological Performance ◽  
Genome Wide ◽  
Genomic Divergence ◽  
Empirical Tests ◽  
Selected Traits ◽  
Stable Genome

AbstractThe transition from ‘well-marked varieties’ of a single species into ‘well-defined species’—especially in the absence of geographic barriers to gene flow (sympatric speciation)—has puzzled evolutionary biologists ever since Darwin1,2. Gene flow counteracts the buildup of genome-wide differentiation, which is a hallmark of speciation and increases the likelihood of the evolution of irreversible reproductive barriers (incompatibilities) that complete the speciation process3. Theory predicts that the genetic architecture of divergently selected traits can influence whether sympatric speciation occurs4, but empirical tests of this theory are scant because comprehensive data are difficult to collect and synthesize across species, owing to their unique biologies and evolutionary histories5. Here, within a young species complex of neotropical cichlid fishes (Amphilophus spp.), we analysed genomic divergence among populations and species. By generating a new genome assembly and re-sequencing 453 genomes, we uncovered the genetic architecture of traits that have been suggested to be important for divergence. Species that differ in monogenic or oligogenic traits that affect ecological performance and/or mate choice show remarkably localized genomic differentiation. By contrast, differentiation among species that have diverged in polygenic traits is genomically widespread and much higher overall, consistent with the evolution of effective and stable genome-wide barriers to gene flow. Thus, we conclude that simple trait architectures are not always as conducive to speciation with gene flow as previously suggested, whereas polygenic architectures can promote rapid and stable speciation in sympatry.

Domestic Violence in Assam: Socio-structural Dynamics

Social Change ◽  
2019 ◽  
Vol 49 (3) ◽  
pp. 391-405
Author(s):  
Joanna Mahjebeen
Keyword(s):  
Domestic Violence ◽  
Structural Dynamics ◽  
Holistic Approach ◽  
Structural Constraints ◽  
High Incidence ◽  
The Status ◽  
Tribal Societies ◽  
Political Milieu ◽  
Crimes Against Women ◽  
Status Of Women

Conventional wisdom would have us believe that Assam is a state where the status of women is comparatively better off than that of their counterparts in the rest of India, that they suffer from fewer instances of domestic violence. The geographical contiguity of a region which contains some matrilineal tribal societies, significant female mobility, and a near absence of practices such as dowry or sati as part of tradition, might lend some credibility to this belief. However, present indicators and crime statistics have actually shown a high incidence of overall crimes against women in Assam. A complex socio-political milieu, characterised by increasing militarism and insurgency, continuing ethnic and group conflicts in an overall environment where ‘market forces’ dominate, has in its own way posed serious challenges to the security of women and led to the opening up of more and more ‘violent spaces’ –the home being one one of them. The present study endeavours to explore the socio-structural dynamics and contexts rooted in Assam that perpetuate domestic violence against women. The study underscores the necessity of informed policy-level interventions and a holistic approach to address structural constraints that underpin such violence.

scholarly journals Shedding Light on the Grey Zone of Speciation along a Continuum of Genomic Divergence

PLoS Biology ◽  
2016 ◽  
Vol 14 (12) ◽  
pp. e2000234 ◽  
Author(s):  
Camille Roux ◽  
Christelle Fraïsse ◽  
Jonathan Romiguier ◽  
Yoann Anciaux ◽  
Nicolas Galtier ◽  
...  
Keyword(s):  
Grey Zone ◽  
Genomic Divergence

Lack of specialization in trophic morphology between genetically differentiated dwarf and normal forms of lake whitefish (Coregonus clupeaformis Mitchill) in Lac de l'Est, Quebec

1996 ◽  
Vol 74 (11) ◽  
pp. 1989-1998 ◽  
Author(s):  
Angelo Chouinard ◽  
Dany Pigeon ◽  
Louis Bernatchez
Keyword(s):  
Gene Flow ◽  
Trophic Ecology ◽  
Early Stage ◽  
Population Divergence ◽  
Gene Pools ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Apparent Lack ◽  
Enzyme Loci ◽  
Trophic Niches

We recently observed a bimodal distribution in size of sexually maturing lake whitefish (Coregonus clupeaformis Mitchill) in Lac de L'Est, Quebec. The objective of this study was to test the hypothesis that these two spawning size classes represent genetically distinct ecotypes, potentially adapted in morphology for occupying different trophic niches. This was accomplished by quantifying the extent of genetic (mitochondrial DNA (mtDNA) and enzyme loci) and morphological differences. Significant differences in haplotype and allele frequency distributions confirmed the hypothesis that whitefish maturing at small (dwarf) and normal sizes are structured into two distinct gene pools. However, low Fst values at mtDNA and enzyme loci, coupled with the apparent lack of spatial and temporal spawning segregation, suggest that reproductive isolation is incomplete and that gene flow is still occurring between the two forms. Patterns of mtDNA diversity favoured the origin of genetically distinct dwarf and normal-size lake whitefish forms in Lac de l'Est through sympatric divergence. However, a lack of differences in morphological traits potentially related to trophic ecology did not support the hypothesis that the two forms represent ecotypes which are morphologically specialized in trophic niches. This study established that sympatric dwarf and normal-size spawning groups of lake whitefish in Lac de l'Est represent two genetically distinct populations despite the potential for gene flow between them. This, coupled with their low level of morphological diversification, suggests that they represent an early stage of population divergence, and therefore makes them of particular interest for understanding the gene–environment processes involved in the early steps of speciation events.

scholarly journals Evolution of cryptic gene pools in Hypericum perforatum: the influence of reproductive system and gene flow

2013 ◽  
Vol 111 (6) ◽  
pp. 1083-1094 ◽  
Author(s):  
Marcus A. Koch ◽  
Charlotte Scheriau ◽  
Anja Betzin ◽  
Nora Hohmann ◽  
Timothy F. Sharbel
Keyword(s):  
Gene Flow ◽  
Reproductive System ◽  
Hypericum Perforatum ◽  
Gene Pools
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