Females with Attractive Mates Gain Environmental Benefits That Increase Lifetime and Multigenerational Fitness.

AbstractResolving the degree to which environmental (direct) versus genetic (indirect) benefits shape female mate choice is a long-standing challenge, particularly for socially monogamous species where male environmental and genetic contributions are difficult to disentangle. This study combines long-term population monitoring with quantitative genetic analyses in a socially monogamous but sexually promiscuous Australian songbird to demonstrate that female mating preferences are driven by nongenetic environmental benefits that increase the fitness of both the female and her offspring. Male Red-backed Fairywrens () flexibly breed in either ornamented or unornamented plumage, and females consistently prefer ornamented males.

Telomere Length is a Susceptibility Marker for Tasmanian Devil Facial Tumor Disease.

Telomeres protect chromosomes from degradation during cellular replication. In humans, it is well-documented that excessive telomere degradation is one mechanism by which cells can become cancerous. Increasing evidence from wildlife studies suggests that telomere length is positively correlated with survival and health and negatively correlated with disease infection intensity.

The age-performance relationship in the general population and strategies to delay age related decline in performance.

The age-performance relationship describes changes in the organism's structural and functional capabilities over the course of the lifespan. The typical, empirical pattern is an asymmetrical inverted-U shape association with peak capacity occurring early in life. This process is well described in the literature, with an increasing interest in features that characterize this pattern, such as the rate of growth, age of peak performance, and rate of decline with aging.

An integrative modeling approach to the age-performance relationship in mammals at the cellular scale.

Physical and cognitive performances change across lifespan. Studying cohorts of individuals in specific age ranges and athletic abilities remains essential in assessing the underlying physiological mechanisms that result in such a drop in performance. This decline is now viewed as a unique phenotypic biomarker and a hallmark of the aging process.

Age-Related Changes in Locomotor Performance Reveal a Similar Pattern for Caenorhabditis elegans, Mus domesticus, Canis familiaris, Equus caballus, and Homo sapiens.

Locomotion is one of the major physiological functions for most animals. Previous studies have described aging mechanisms linked to locomotor performance among different species. However, the precise dynamics of these age-related changes, and their interactions with development and senescence, are largely unknown.

Modeling of genetic gain for single traits from marker-assisted seedling selection in clonally propagated crops.

Seedling selection identifies superior seedlings as candidate cultivars based on predicted genetic potential for traits of interest. Traditionally, genetic potential is determined by phenotypic evaluation. With the availability of DNA tests for some agronomically important traits, breeders have the opportunity to include DNA information in their seedling selection operations-known as marker-assisted seedling selection.

Evolution of the additive genetic variance-covariance matrix under continuous directional selection on a complex behavioural phenotype.

Given the pace at which human-induced environmental changes occur, a pressing challenge is to determine the speed with which selection can drive evolutionary change. A key determinant of adaptive response to multivariate phenotypic selection is the additive genetic variance-covariance matrix ( G: ). Yet knowledge of G: in a population experiencing new or altered selection is not sufficient to predict selection response because G: itself evolves in ways that are poorly understood.

Genetic variation, simplicity, and evolutionary constraints for function-valued traits.

Understanding the patterns of genetic variation and constraint for continuous reaction norms, growth trajectories, and other function-valued traits is challenging. We describe and illustrate a recent analytical method, simple basis analysis (SBA), that uses the genetic variance-covariance (G) matrix to identify "simple" directions of genetic variation and genetic constraints that have straightforward biological interpretations. We discuss the parallels between the eigenvectors (principal components) identified by principal components analysis (PCA) and the simple basis (SB) vectors identified by SBA.

Aggressive behavior, brain size and domestication in clonal rainbow trout lines.

Domestication causes behavior and brain size changes in many species. We addressed three questions using clonal rainbow trout lines: What are the mirror-elicited aggressive tendencies in lines with varying degrees of domestication? How does brain size relate to genotype and domestication level? Finally, is there a relationship between aggressive behavior and brain size? Clonal lines, although sampling a limited subset of the species variation, provide us with a reproducible experimental system with which we can develop hypotheses for further research. We performed principal component analyses on 12 continuous behavior and brain/body size variables and one discrete behavioral variable ("yawn") and detected several aggression syndromes.

Warped functional analysis of variance.

This article presents an Analysis of Variance model for functional data that explicitly incorporates phase variability through a time-warping component, allowing for a unified approach to estimation and inference in presence of amplitude and time variability. The focus is on single-random-factor models but the approach can be easily generalized to more complex ANOVA models. The behavior of the estimators is studied by simulation, and an application to the analysis of growth curves of flour beetles is presented.

Endocrine rhythms in the brown bear (Ursus arctos): Evidence supporting selection for decreased pineal gland size.

Many temperate zone animals adapt to seasonal changes by altering their physiology. This is mediated in large part by endocrine signals that encode day length and regulate energy balance and metabolism. The objectives of this study were to determine if the daily patterns of two important hormones, melatonin and cortisol, varied with day length in captive brown bears (Ursus arctos) under anesthetized and nonanesthetized conditions during the active (March-October) and hibernation periods.

Oxidative stress among SOD-1 genotypes in rainbow trout (Oncorhynchus mykiss).

Natural variation in the antioxidant-enzyme SOD-1 (superoxide dismutase) is known to alter the impacts of oxidative damage at both the cellular and organismal levels. Using three homozygous clonal lines of rainbow trout [Hot Creek (n=30), Arlee (n=21), and Swanson (n=10)], which differ for single nucleotide polymorphisms (SNPs) and amino acid substitutions at the SOD-1 locus, we investigated the functional effects of this variation on SOD-1 activity during ozone stress and subsequent levels of oxidative damage to DNA and cell membranes. Fish from each line were subjected to either control conditions or 24h of ozone stress, after which tissues were analyzed for antioxidant status and oxidative damage.

Limits to behavioral evolution: the quantitative genetics of a complex trait under directional selection.

Replicated selection experiments provide a powerful way to study how "multiple adaptive solutions" may lead to differences in the quantitative-genetic architecture of selected traits and whether this may translate into differences in the timing at which evolutionary limits are reached. We analyze data from 31 generations (n=17,988) of selection on voluntary wheel running in house mice. The rate of initial response, timing of selection limit, and height of the plateau varied significantly between sexes and among the four selected lines.

Sclerotinia sclerotiorum populations infecting canola from China and the United States are genetically and phenotypically distinct.

Genetic and phenotypic diversity and population differentiation of Sclerotinia sclerotiorum isolates infecting canola from China and the United States were investigated. Genetic diversity was assessed with eight microsatellite markers and mycelial compatibility groups (MCGs). Phenotypic diversity was assessed with sensitivity to three fungicides, production of oxalate and sclerotia, growth rate, and virulence on two canola cultivars.

Basal metabolic rate of aged mice is affected by random genetic drift but not by selective breeding for high early-age locomotor activity or chronic wheel access.

The study of correlated evolution can lead to new insights about the inheritance patterns of complex traits. In order to better understand the evolution of metabolic rate, we tested whether voluntary activity levels and basal metabolic rate are genetically correlated in 90-wk-old mice (Mus domesticus) from replicated lines of the sixteenth generation of an artificial selection experiment for high early-age wheel-running activity. We measured basal rates of oxygen consumption and carbon dioxide production and also computed the respiratory exchange ratio.

The relative importance of genetics and phenotypic plasticity in dictating bone morphology and mechanics in aged mice: evidence from an artificial selection experiment.

Both genetic and environmental factors are known to influence the structure of bone, contributing to its mechanical behavior during, and adaptive response to, loading. We introduce a novel approach to simultaneously address the genetically mediated, exercise-related effects on bone morphometrics and strength, using mice that had been selectively bred for high levels of voluntary wheel running (16 generations). Female mice from high running and control lines were either allowed (n=12, 12, respectively) or denied (n=11, 12, respectively) access to wheels for 20 months.

Number of arginine-vasopressin neurons in the suprachiasmatic nuclei is not related to level or circadian characteristics of wheel-running activity in house mice.

House mouse lines bidirectionally selected for nest-building behavior show a correlation between number of AVP cells in the suprachiasmatic nuclei (SCN), the master circadian clock in mammals, and level of nest-building behavior as well as a correlation between wheel-running activity and SCN AVP content. Similar genetic correlations between wheel-running activity and nest-building behavior have been reported in house mouse lines selected for increased voluntary wheel-running behavior. These similarities in genetic correlation structure in independently selected mouse lines allowed us to test whether AVP in the SCN and wheel running activity are truly correlated traits under identical testing procedures.

Different effects of intensity and duration of locomotor activity on circadian period.

An outstanding unresolved issue in chronobiology is how the level of locomotor activity influences length of the free-running, endogenous circadian period (tau). To address this issue, the authors studied a novel model, 4 replicate lines of laboratory house mice (Mus domesticus) that had been selectively bred for high wheel-running activity (S) and their 4 unselected control (C) lines. Previous work indicates that S mice run approximately twice as many revolutions/day and exhibit an altered dopaminergic function as compared with C mice.

Food wasting by house mice: variation among individuals, families, and genetic lines.

Under ad libitum conditions, laboratory house mice (Mus domesticus) fragment considerable amounts of pelleted food and leave it scattered in their cages. The proportion of food thus wasted (in relation to food eaten) varies remarkably among individuals, from 2% to 40%, but is highly consistent in consecutive trials, even when the mice were moved from 22 to -10 degrees C and food consumption doubled. Food wasting did not differ either between the sexes or between genetic lines that had been selected (10 generations) for high voluntary wheel-running behavior (n=4) and their unselected control lines (n=4).

Ontogenies in mice selected for high voluntary wheel-running activity. I. Mean ontogenies.

The evolutionary importance of postnatal ontogenies has long been recognized, but most studies of ontogenetic trajectories have focused exclusively on morphological traits. For animals, this represents a major omission because behavioral traits and their ontogenies often have relatively direct relationships to fitness. Here four replicate lines of house mice artificially selected for high early-age wheel running and their four replicate control lines were used to evaluate the effects of early-age directional selection, genetic drift, and activity environment (presence or absence of a running wheel) on variation in the ontogenies of three traits known to be genetically correlated: voluntary wheel running, body mass, and food consumption.

Dominance, plasma testosterone levels, and testis size in house mice artificially selected for high activity levels.

Male house mice (Mus domesticus) from four replicate lines selectively bred for high voluntary wheel-running behavior were compared with four random-bred control lines with respect to dominance, testis size, and plasma testosterone level. Behavior was measured with a tube apparatus in which focal mice encountered a standard opponent from an inbred strain, and positions of mice were scored over a 10-min period; the test was replicated the following day. Blood samples were taken from undisturbed mice 1 week prior to testing (baseline condition) and immediately after the first tube test; plasma testosterone was measured by enzyme immunoassay with chromatography.

Antioxidant gene expression in active and sedentary house mice (Mus domesticus) selected for high voluntary wheel-running behavior.

We present liver mRNA levels of the two antioxidant enzymes catalase (CAT) and Mn-superoxide dismutase (SOD2) in four treatment groups of house mice assayed by RNase protection at 20 months of age. These groups were mice from four replicate selection and four replicate control lines from the sixteenth generation of selective breeding for high voluntary wheel running, housed with or without running wheels from age 3 weeks through 20 months. Exercising control females had induced CAT expression; SOD2 exhibited a similar pattern in females from two of the four control lines.

Evolution of a small-muscle polymorphism in lines of house mice selected for high activity levels.

To study the correlated evolution of locomotor behavior and exercise physiology, we conducted an artificial selection experiment. From the outbred Hsd:ICR strain of Mus domesticus, we began eight separate lines, each consisting of 10 breeding pairs. In four of the lines, we used within-family selection to increase voluntary wheel running.

Alcohol consumption promotes body weight loss in melanoma-bearing mice.

Background: Alcohol consumption is an important risk factor for cancer. Little is known about its effects on cancer progression. Previously, we showed that high ethanol consumption inhibited metastasis of B16BL6 melanoma-bearing mice without affecting primary tumor growth.