Search results for " Selection"

Data from: Multiple quantitative trait loci influence intra-specific variation in genital morphology between phylogenetically distinct lines of Droso…

2011

The evolution of animal genitalia has gained renewed interest, because of their potential roles during sexual selection and early stages of species formation. Although central to understanding the evolutionary process, knowledge of the genetic basis of natural variation in genital morphology is limited to a very few species. Using an out-bred cross between phylogenetically distinct lines of Drosophila montana, we characterized quantitative trait loci (QTLs) affecting the size and shape of the distiphallus, a prominent part of the male intromittent organ. Our microsatellite-based linkage analysis shows that intra-specific variation of the distiphallus involves several QTLs of largely additiv…

Data from: No evidence for prezygotic postcopulatory avoidance of kin despite high inbreeding depression

2018

Offspring resulting from mating among close relatives can suffer from impaired fitness through the expression of recessive alleles with deleterious effects. Post-copulatory sperm selection (a pre-zygotic mechanism of cryptic female choice) has been suggested to be an effective way to avoid inbreeding. To investigate whether post-copulatory female choice allows avoiding fertilization by close kin, we performed artificial inseminations in a promiscuous bird, the houbara bustard (Chlamydotis undulata undulata). Females were inseminated with a mix of sperm from triads of males, each constituted of a male genetically unrelated to the female, a first cousin, and a half-sibling. When counting the …

Data from: Postmating-prezygotic isolation between two allopatric populations of Drosophila montana: fertilisation success differs under sperm compet…

2017

Postmating but prezygotic (PMPZ) interactions are increasingly recognized as a potentially important early-stage barrier in the evolution of reproductive isolation. A recent study described a potential example between populations of the same species: single matings between Drosophila montana populations resulted in differential fertilisation success because of the inability of sperm from one population (Vancouver) to penetrate the eggs of the other population (Colorado). As the natural mating system of D. montana is polyandrous (females remate rapidly), we set up double matings of all possible crosses between the same populations to test whether competitive effects between ejaculates influe…

Data from: Negative frequency-dependent selection of sexually antagonistic alleles in Myodes glareolus

2011

Sexually antagonistic genetic variation, where optimal values of traits are sex-dependent, is known to slow the loss of genetic variance associated with directional selection on fitness-related traits. However, sexual antagonism alone is not sufficient to maintain variation indefinitely. Selection of rare forms within the sexes can help to conserve genotypic diversity. We combined theoretical models and a field experiment with Myodes glareolus to show that negative frequency-dependent selection on male dominance maintains variation in sexually antagonistic alleles. In our experiment, high-dominance male bank voles were found to have low-fecundity sisters, and vice versa. These results show …

Data from: Very high MHC Class IIB diversity without spatial differentiation in the Mediterranean population of Greater Flamingos

2017

MHC Class II Genotype data Greater Flamingo MHC Class IIB genoptype data of four Mediterranean breeding colonies: France, Spain, Algeria and Turkey MHCClassIIGenotypeGreaterFlamingo.xlsx

Data from: Inbreeding reveals mode of past selection on male reproductive characters in Drosophila melanogaster

2013

Directional dominance is a prerequisite of inbreeding depression. Directionality arises when selection drives alleles that increase fitness to fixation and eliminates dominant deleterious alleles, while deleterious recessives are hidden from it and maintained at low frequencies. Traits under directional selection (i.e., fitness traits) are expected to show directional dominance and therefore an increased susceptibility to inbreeding depression. In contrast, traits under stabilizing selection or weakly linked to fitness are predicted to exhibit little-to-no inbreeding depression. Here, we quantify the extent of inbreeding depression in a range of male reproductive characters and then infer t…

Recognition of Cardiac Arrhythmia by Means of Beat Clustering on ECG-Holter Recordings

2012

The follow-up of some cardiac diseases may be achieved by ECG-holter record analysis. A heartbeat clustering method can be used to reduce the usually high computational cost of such Holter analysis. This study describes a method aimed at cardiac arrhythmia recognition based on this approach, by means of unsupervised inspection of morphologically similar heartbeat groups. Singular Value Decomposition (SVD) is used as the feature selection method since the complexity increases exponentially with the number of features. A modification of the k-means algorithm was developed for centroid computation, taking into account heartbeat length changes. Experimental set consisted of ECG records from the…

Inclusion of pregnant women in clinical trials of COVID-19 therapies: what have we learned?

2020

Impact of vCJD on blood supply.

2007

Variant Creutzfeldt-Jakob disease (vCJD) is an at present inevitably lethal neurodegenerative disease which can only be diagnosed definitely post mortem. The majority of the approximately 200 victims to date have resided in the UK where most contaminated beef materials entered the food chain. Three cases in the UK demonstrated that vCJD can be transmitted by blood transfusion. Since BSE and vCJD have spread to several countries outside the UK, it appears advisable that specific risk assessments be carried out in different countries and geographic areas. This review explains the approach adopted by Germany in assessing the risk and considering precautionary measures. A fundamental premise is…

Endoscopic and surgical resection of T1a/T1b esophageal neoplasms: A systematic review

2013

AIM: To investigate potential therapeutic recommendations for endoscopic and surgical resection of T1a/T1b esophageal neoplasms. METHODS: A thorough search of electronic databases MEDLINE, Embase, Pubmed and Cochrane Library, from 1997 up to January 2011 was performed. An analysis was carried out, pooling the effects of outcomes of 4241 patients enrolled in 80 retrospective studies. For comparisons across studies, each reporting on only one endoscopic method, we used a random effects meta-regression of the log-odds of the outcome of treatment in each study. “Neural networks” as a data mining technique was employed in order to establish a prediction model of lymph node status in superficial …