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

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.

Confronting the grey zone after severe brain injury

2019 ◽  
Vol 3 (6) ◽  
pp. 707-711 ◽  
Author(s):  
Andrew Peterson ◽  
Adrian M. Owen
Keyword(s):  
Brain Injury ◽  
Ethical Issues ◽  
Vegetative State ◽  
Clinical Care ◽  
Grey Zone ◽  
Severe Brain Injury ◽  
New Methods ◽  
Legal Decision Making ◽  
Technological Developments ◽  
The Brain

In recent years, rapid technological developments in the field of neuroimaging have provided several new methods for revealing thoughts, actions and intentions based solely on the pattern of activity that is observed in the brain. In specialized centres, these methods are now being employed routinely to assess residual cognition, detect consciousness and even communicate with some behaviorally non-responsive patients who clinically appear to be comatose or in a vegetative state. In this article, we consider some of the ethical issues raised by these developments and the profound implications they have for clinical care, diagnosis, prognosis and medical-legal decision-making after severe brain injury.

Grey Zone Lymphoma in Children and Adolescents: Experience of Pediatric Hodgkin and Non-Hodgkin Study Groups

2014 ◽  
Vol 226 (02) ◽  
Author(s):  
B Burkhardt ◽  
D Körholz ◽  
W Klapper ◽  
W Woessmann ◽  
C Mauz-Körholz
Keyword(s):  
Children And Adolescents ◽  
Study Groups ◽  
Grey Zone

Fractional Flow Reserve: Does a Cut-off Value add Value?

2016 ◽  
Vol 11 (1) ◽  
pp. 17
Author(s):  
Shah R Mohdnazri ◽  
◽  
◽  
◽  
Thomas R Keeble ◽  
...  
Keyword(s):  
Fractional Flow Reserve ◽  
Coronary Intervention ◽  
Grey Zone ◽  
Fractional Flow ◽  
Non Invasive ◽  
Invasive Test ◽  
Flow Reserve ◽  
A Value ◽  
Percutaneous Coronary ◽  
Value Add

Fractional flow reserve (FFR) has been shown to improve outcomes when used to guide percutaneous coronary intervention (PCI). There have been two proposed cut-off points for FFR. The first was derived by comparing FFR against a series of non-invasive tests, with a value of ≤0.75 shown to predict a positive ischaemia test. It was then shown in the DEFER study that a vessel FFR value of ≥0.75 was associated with safe deferral of PCI. During the validation phase, a ‘grey zone’ for FFR values of between 0.76 and 0.80 was demonstrated, where a positive non-invasive test may still occur, but sensitivity and specificity were sub-optimal. Clinical judgement was therefore advised for values in this range. The FAME studies then moved the FFR cut-off point to ≤0.80, with a view to predicting outcomes. The ≤0.80 cut-off point has been adopted into clinical practice guidelines, whereas the lower value of ≤0.75 is no longer widely used. Here, the authors discuss the data underpinning these cut-off values and the practical implications for their use when using FFR guidance in PCI.

Why Do We Need New Markers for Male Hypogonadism and How Seminal Proteomics Might Solve the Problem?

2020 ◽  
Vol 27 (12) ◽  
pp. 1186-1191
Author(s):  
Giuseppe Grande ◽  
Domenico Milardi ◽  
Silvia Baroni ◽  
Andrea Urbani ◽  
Alfredo Pontecorvi
Keyword(s):  
Serum Testosterone ◽  
Clinical Syndrome ◽  
Testosterone Replacement ◽  
Total Testosterone ◽  
Male Hypogonadism ◽  
Grey Zone ◽  
Testosterone Levels ◽  
Normal Number ◽  
Replacement Treatment

Male hypogonadism is “a clinical syndrome that results from failure of the testis to produce physiological concentrations of testosterone and/or a normal number of spermatozoa due to pathology at one or more levels of the hypothalamic– pituitary–testicular axis”. The diagnostic protocol of male hypogonadism includes accurate medical history, physical exam, as well as hormone assays and instrumental evaluation. Basal hormonal evaluation of serum testosterone, LH, and FSH is important in the evaluation of diseases of the hypothalamus-pituitary-testis axis. Total testosterone levels < 8 nmol/l profoundly suggest the diagnosis of hypogonadism. An inadequate androgen status is moreover possible if the total testosterone levels are 8-12 nmol/L. In this “grey zone” the diagnosis of hypogonadism is debated and the appropriateness for treating these patients with testosterone should be fostered by symptoms, although often non-specific. Up to now, no markers of androgen tissue action can be used in clinical practice. The identification of markers of androgens action might be useful in supporting diagnosis, Testosterone Replacement Treatment (TRT) and clinical follow-up. The aim of this review is to analyze the main findings of recent studies in the field of discovering putative diagnostic markers of male hypogonadism in seminal plasma by proteomic techniques. The identified proteins might represent a “molecular androtest” useful as a seminal fingerprint of male hypogonadism, for the diagnosis of patients with moderate grades of testosterone reduction and in the follow-up of testosterone replacement treatment.

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