Search results for "selection"
showing 10 items of 1940 documents
Patient-reported impact of Charcot-Marie-Tooth disease: protocol for a real-world digital lifestyle study
2021
Abstract Background Charcot-Marie-Tooth disease (CMT) is a rare, chronic, progressive motor and sensory neuropathy that affects the peripheral nervous system, leading to progressive, predominantly distal muscle weakness, atrophy, sensory loss and progressive limb dysfunction. As with many rare diseases, there is a lack of patient-reported data with which to understand and address patient needs. This study aims to explore the real-world impact of CMT from the patient perspective. Methods This is a prospective, digital lifestyle study of at least 2,000 people with CMT, >18 years, resident in the following countries: France, Germany, Italy, Spain, the UK and the USA. Participants will be re…
Oh sister, where art thou? Spatial population structure and the evolution of an altruistic defence trait.
2014
The evolution of parasite virulence and host defences is affected by population structure. This effect has been confirmed in studies focusing on large spatial scales, whereas the importance of local structure is not well understood. Slavemaking ants are social parasites that exploit workers of another species to rear their offspring. Enslaved workers of the host species Temnothorax longispinosus have been found to exhibit an effective post-enslavement defence behaviour: enslaved workers were observed killing a large proportion of the parasites’ offspring. As enslaved workers do not reproduce, they gain no direct fitness benefit from this ‘rebellion’ behaviour. However, there may be an indir…
The extent of variation in male song, wing and genital characters among allopatric Drosophila montana populations.
2007
Drosophila montana, a species of the Drosophila virilis group, has distributed around the northern hemisphere. Phylogeographic analyses of two North American and one Eurasian population of this species offer a good background for the studies on the extent of variation in phenotypic traits between populations as well as for tracing the selection pressures likely to play a role in character divergence. In the present paper, we studied variation in the male courtship song, wing and genital characters among flies from Colorado (USA), Vancouver (Canada) and Oulanka (Finland) populations. The phenotypic divergence among populations did not coincide with the extent of their genetic divergence, sug…
Biochemical selection of prepubertal patients with androgen insensitivity syndrome by sex hormone-binding globulin response to the human chorionic go…
1997
Before puberty, the diagnosis of androgen insensitivity syndrome (AIS) can be difficult. We studied whether the decrease of sex hormone-binding globulin (SHBG) during the human chorionic gonadotropin (hCG) test may represent a biochemical test to select prepubertal patients with AIS. We examined prepubertal patients with AIS (n = 9, age 0.9-8.2 y), male pseudohermaphroditism not due to AIS (other-MPH) (n = 8, age 0.6-10.7 y), and control boys (n = 12, age 0.8-12.5 y). Testosterone and SHBG levels (mean +/- SD) were measured before (d 0) and after (d 5) a hCG test (1500 IU X 3 d). Testosterone levels (nmol/L) increased in all groups [AIS: from 1.5 +/- 1.2 to 22.1 +/- 11.8 (p0.001); other-MPH…
Striated muscle-specific serine/threonine-protein kinase beta (SPEGβ) segregates with high- versus low-responsiveness to endurance exercise training
2019
Bidirectional selection for either high or low responsiveness to endurance running has created divergent rat phenotypes of high-response trainers (HRT) and low-response trainers (LRT). We conducted proteome profiling of HRT and LRT gastrocnemius of 10 female rats (body weight 279 ± 35 g; n = 5 LRT and n = 5 HRT) from generation 8 of selection. Differential analysis of soluble proteins from gastrocnemius was conducted by label-free quantitation. Genetic association studies were conducted in 384 Russian international-level athletes (age 23.8 ± 3.4 yr; 202 men and 182 women) stratified to endurance or power disciplines. Proteomic analysis encompassed 1,024 proteins, 76 of which exhibited stat…
Trade-off between warning signal efficacy and mating success in the wood tiger moth
2011
The coloration of species can have multiple functions, such as predator avoidance and sexual signalling, that directly affect fitness. As selection should favour traits that positively affect fitness, the genes underlying the trait should reach fixation, thereby preventing the evolution of polymorphisms. This is particularly true for aposematic species that rely on coloration as a warning signal to advertise their unprofitability to predators. Nonetheless, there are numerous examples of aposematic species showing remarkable colour polymorphisms. We examined whether colour polymorphism in the wood tiger moth is maintained by trade-offs between different functions of coloration. In Finland, m…
No room for males in caves: Female-biased sex ratio in subterranean amphipods of the genus Niphargus.
2021
Sex allocation theory predicts that the proportion of daughters to sons will evolve in response to ecological conditions that determine the costs and benefits of producing each sex. All else being equal, the adult sex ratio (ASR) should also vary with ecological conditions. Many studies of subterranean species reported female-biased ASR, but no systematic study has yet been conducted. We test the hypothesis that the ASR becomes more female-biased with increased isolation from the surface. We compiled a data set of ASRs of 35 species in the subterranean amphipod Niphargus, each living in one of three distinct habitats (surface-subterranean boundary, cave streams, phreatic lakes) representing…
Beyond lifetime reproductive success: the posthumous reproductive dynamics of male Trinidadian guppies
2013
In semelparous populations, dormant germ banks (e.g. seeds) have been proposed as important in maintaining genotypes that are adaptive at different times in fluctuating environments. Such hidden storage of genetic diversity need not be exclusive to dormant banks. Genotype diversity may be preserved in many iteroparous animals through sperm-storage mechanisms in females. This allows males to reproduce posthumously and increase the effective sizes of seemingly female-biased populations. Although long-term sperm storage has been demonstrated in many organisms, the understanding of its importance in the wild is very poor. We here show the prevalence of male posthumous reproduction in wild Trini…
Preconception sex selection demand and preferences in the United States
2005
Objective Preconception sex selection for nonmedical reasons raises important moral, legal, and social issues. The main concern is based upon the assumption that a widely available service for sex selection will lead to a socially disruptive imbalance of the sexes. For a severe sex ratio distortion to occur, however, at least two conditions have to be met. First, there must be a significant preference for children of a particular sex, and second, there must be a considerable interest in employing sex selection technology. Our objective was to ascertain such demand and preferences among the United States general population. Design Cross-sectional web-based survey. Setting United States gener…
A trade-off between sexual signalling and immune function in a natural population of the drumming wolf spider Hygrolycosa rubrofasciata.
2005
The field of ecological immunology is ultimately seeking to address the question ‘Why is there variation in immune function?’ Here, we provide experimental evidence that costs of ubiquitous sexual signals are a significant source of variation in immune function. In the mating season, males of the wolf spider Hygrolycosa rubrofasciata drum against dry leaves while wandering around the habitat searching for receptive females. According to a previous study, the male metabolic rate during the drumming increases 22-fold compared to the resting metabolic rate. In the present study, we examined whether investment in costly courtship drumming decreases male immune function in a wild population of H…