Search results for " selection"

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…

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…

Sexual differences in larval life history traits of acanthocephalan cystacanths

2006

Sexual differences in life history traits, such as size dimorphism, presumably arise via sexual selection and are most readily observed in adults. For complex life-cycle parasites, however, sexual selection may also have consequences for larval traits, e.g., growth in intermediate hosts. Two acanthocephalan species (Acanthocephalus lucii and Echinorhynchus borealis) were studied to determine, whether larval life histories differ between males and females. The size of female A. lucii cystacanths had a much stronger relationship with intermediate host size than males, suggesting females invest more in growth and are consequently more limited by resources. No relationship between host size and…

Outcome of extracorporeal membrane oxygenation support for high-risk percutaneous coronary intervention in non-ST-segment elevation acute coronary sy…

2020

Causes of ineligibility in randomized controlled trials and long-term mortality in patients with non-ST-segment elevation acute coronary syndromes

2006

To determine the long-term mortality of patients with non-ST-segment elevation acute coronary syndromes (NSTEACS) that are eligible versus those not eligible in randomized controlled trials (RCT), and how each exclusion criteria is associated with outcome.Common causes of exclusion in six published RCT on intravenous antithrombotic therapy were prospectively assessed in a cohort of 452 consecutive patients with NSTEACS that were followed for up to 3 years.Forty-one percent of patients had one or more exclusion criteria establishing the ineligible group. These patients were older, more likely to have coronary risk factors, ischemic ECG changes, heart failure at admission, higher creatinine l…