Search results for "Succe"
showing 10 items of 990 documents
Intralocus sexual conflict for fitness: sexually antagonistic alleles for testosterone
2011
Intralocus sexual conflict occurs when a trait encoded by the same genetic locus in the two sexes has different optima in males and females. Such conflict is widespread across taxa, however, the shared phenotypic traits that mediate the conflict are largely unknown. We examined whether the sex hormone, testosterone (T), that controls sexual differentiation, contributes to sexually antagonistic fitness variation in the bank vole, Myodes glareolus . We compared (opposite-sex) sibling reproductive fitness in the bank vole after creating divergent selection lines for T. This study shows that selection for T was differentially associated with son versus daughter reproductive success, causing a …
Sperm competition accentuates selection on ejaculate attributes.
2019
Ejaculate attributes are important factors driving the probability of fertilizing eggs. When females mate with several males, competition between sperm to fertilize eggs should accentuate selection on ejaculate attributes. We tested this hypothesis in the North African houbara bustard ( Chlamydotis undulata undulata ) by comparing the strength of selection acting on two ejaculate attributes when sperm from single males or sperm from different males were used for insemination. In agreement with the prediction, we found that selection on ejaculate attributes was stronger when sperm of different males competed for egg fertilization. These findings provide the first direct comparison of the st…
Intra‐ and Intersexual Trade‐Offs between Testosterone and Immune System: Implications for Sexual and Sexually Antagonistic Selection
2010
International audience; Parasites indirectly affect life-history evolution of most species. Combating parasites requires costly immune defenses that are assumed to trade off with other life-history traits. In vertebrate males, immune defense is thought to trade off with reproductive success, as androgens enhancing sexual signaling can suppress immunity. The phenotypic relationship between male androgen levels and immune function has been addressed in many experimental studies. However, these do not provide information on either intra- or intersex genetic correlations, necessary for understanding sexual and sexually antagonistic selection theories. We measured male and female humoral antibod…
Associations of overweight and metabolic health with successful aging: 32-year follow-up of the Helsinki Businessmen Study
2020
Background & aims: Prognostic significance of metabolically healthy overweight and obesity (MHO) is under debate. However the relationship between MHO and health-related quality of life (HRQoL) is less studied. We compared successful aging (longevity plus HRQoL) in men with MHO, metabolically healthy normal weight (MHN) and metabolically unhealthy overweight and obesity (MUO). Methods: In the Helsinki Businessmen Study longitudinal cohort, consisting of men born 1919 to 1934. In 1985/86, overweight (BMI >= 25 kg/m(2)) and metabolic health were determined in 1309 men (median age 60 years). HRQoL was assessed using RAND-36/SF-36 in 2000 and 2007, and all-cause mortality retrieved from registe…
Balancing selection maintains polymorphisms at neurogenetic loci in field experiments
2017
Most variation in behavior has a genetic basis, but the processes determining the level of diversity at behavioral loci are largely unknown for natural populations. Expression of arginine vasopressin receptor 1a (Avpr1a) and oxytocin receptor (Oxtr) in specific regions of the brain regulates diverse social and reproductive behaviors in mammals, including humans. That these genes have important fitness consequences and that natural populations contain extensive diversity at these loci implies the action of balancing selection. In Myodes glareolus, Avpr1a and Oxtr each contain a polymorphic microsatellite locus located in their 5′ regulatory region (the regulatory region-associated microsatel…
Reducing Stress and Enhancing Academic Buoyancy among Adolescents Using a Brief Web-based Program Based on Acceptance and Commitment Therapy : A Rand…
2018
Acceptance and commitment therapy programs have rarely been used as preventive tools for alleviating stress and enhancing coping skills among adolescents. This randomized controlled trial examined the efficacy of a novel Finnish web- and mobile-delivered five-week intervention program called Youth COMPASS among a general sample of ninth-grade adolescents (n= 249, 49% females). The intervention group showed a small but significant decrease in overall stress (between-group Cohen’s d = 0.22) and an increase in academic buoyancy (d= 0.27). Academic skills did not influence the intervention gains, but the intervention gains were largest among high-stressed participants. The results suggest that …
Dispositional hope and life satisfaction among older adults attending lifelong learning programs
2016
Abstract Background The aim of this study is to explore the indirect effects of dispositional hope in the life satisfaction of older adults attending a lifelong learning program at the University of Valencia, Spain. We examine the mediating impact of dispositional hope regarding its ability to impact life satisfaction while considering affective and confidant social support, perceived health and leisure activities, consciousness and spirituality as predictors. Methods Analysis were based on survey data (response rate 77.4%) provided by 737 adults 55 years old or more (Mean age = 65.41, SD = 6.60; 69% woman). A structural model with latent variables was specified and estimated in Mplus. Resu…
Sexual activity and life satisfaction in older adults
2018
Aim Based on the concept of successful ageing and research reports on the benefits of maintaining sexual activity in mid- to late life, the purpose of the current study was to examine the relationship between global life satisfaction and sexual satisfaction in adults older than 60 years. The study also analyzed the relationship between various forms of sexual activity (genital and non-genital) and both types of satisfaction. Methods Thirty-three men and 50 women (N =83) were interviewed by using two structuralized questionnaires. Global life satisfaction was measured with Diener's Satisfaction with Life Scale, whereas sexual satisfaction and preferences regarding various intimate behaviours…
HLA and KIR Frequencies in Sicilian Centenarians
2010
Several studies suggest that human longevity appears to be linked inextricably with optimal functioning of the immune system, suggesting that specific genetic determinants may reside in loci that regulate the immune response, as human leukocyte antigen (HLA) and killer cell immunoglobulin-like receptor (KIR) genes. It has been suggested that longevity is associated with positive selection of alleles (i.e., HLA-DR11) or haplotypes (i.e., HLA-B8,DR3) that confer resistance to infectious disease(s). On the other hand, the cytolytic activity of natural killer (NK) cells is controlled by activating and inhibitory cell-surface receptors, including KIR. The genetic diversity of the KIR loci with r…
Genetic signatures of centenarians: Implications for achieving successful aging
2019
The extraordinary rise in the old population in the Western world underscores the importance of studies on aging and longevity to decrease the medical, economic and social problems associated with the increased number of non-autonomous individuals affected by invalidating pathologies. Centenarians have reached the extreme limits of the human life span. They are the best example of extreme longevity, representing selected individuals in which the appearance of major age-related diseases has been consistently delayed or avoided. There is growing evidence that the genetic component of longevity becomes higher with survival at the age of over 90 years. For centenaries, it reaches up to 33% for…