Genetic differentiation in an endangered and strongly philopatric, migrant shorebird.

Background: Populations living in fragmented habitats may suffer from loss of genetic variation and reduced between-patch dispersal, which are processes that can result in genetic differentiation. This occurs frequently in species with reduced mobility, whereas genetic differentiation is less common among mobile species such as migratory birds. The high dispersal capacity in the latter species usually allows for gene flow even in fragmented landscapes.

Stress-related changes in leukocyte profiles and telomere shortening in the shortest-lived tetrapod, Furcifer labordi.

Background: Life history theory predicts that during the lifespan of an organism, resources are allocated to either growth, somatic maintenance or reproduction. Resource allocation trade-offs determine the evolution and ecology of different life history strategies and define an organisms' position along a fast-slow continuum in interspecific comparisons. Labord's chameleon (Furcifer labordi) from the seasonal dry forests of Madagascar is the tetrapod species with the shortest reported lifespan (4-9 months).

Effects of male telomeres on probability of paternity in sand lizards.

Standardized swim-up trials are used in fertilization clinics to select particularly motile spermatozoa in order to increase the probability of a successful fertilization. Such trials demonstrate that sperm with longer telomeres have higher motility and lower levels of DNA damage. Regardless of whether sperm motility, and successful swim-up to fertilization sites, is a direct or correlational effect of telomere length or DNA damage, covariation between telomere length and sperm performance predicts a relationship between telomere length and probability of paternity in sperm competition, a prediction that for ethical reasons cannot be tested on humans.

Telomere length covaries with personality in wild brown trout.

The prevalence of consistent among-individual differences in behaviour, or personality, makes adaptive sense if individuals differ in stable state variables that shift the balance between the costs and benefits of their behavioural decisions. These differences may give rise to both individual differences in, and covariance among, behaviours that influence an individual's exposure to risks. We here study the link between behaviour and a candidate state variable previously overlooked in the study of state-dependent personality variation: telomere length.

Kin selection and polygyny: can relatedness lower the polygyny threshold?

Resource polygyny incurs costs of having to share breeding resources for female breeders. When breeding with a relative, however, such costs may be lessened by indirect fitness benefits through kin selection, while benefits from mutualistic behaviour, such as communal defence, may increase. If so, females should be less resistant to sharing a territory with a related female than with a non-related one.

Rapid growth accelerates telomere attrition in a transgenic fish.

Background: Individuals rarely grow as fast as their physiologies permit despite the fitness advantages of being large. One reason may be that rapid growth is costly, resulting for example in somatic damage. The chromosomal ends, the telomeres, are particularly vulnerable to such damage, and telomere attrition thus influences the rate of ageing.

Telomere dynamics in wild brown trout: effects of compensatory growth and early growth investment.

After a period of food deprivation, animals often respond with a period of faster than normal growth. Such responses have been suggested to result in decreased chromosomal maintenance, which in turn may affect the future fitness of an individual. Here, we present a field experiment in which a food deprivation period of 24 days was enforced on fish from a natural population of juvenile brown trout (Salmo trutta) at the start of the high-growth season in spring.

Telomere dynamics in a long-lived bird, the barnacle goose.

Background: Theories of ageing predict a trade-off between metabolism, reproduction, and maintenance. Species with low investment in early reproduction are thus expected to be able to evolve more efficient maintenance and repair mechanisms, allowing for a longer potential life span (intrinsic longevity). The erosion of telomeres, the protective caps at the ends of linear chromosomes, plays an important role in cellular and organismal senescence, signalling the onset of age-related disease due to accumulation of unrepaired somatic damage.

Sex differences in sand lizard telomere inheritance: paternal epigenetic effects increases telomere heritability and offspring survival.

Background: To date, the only estimate of the heritability of telomere length in wild populations comes from humans. Thus, there is a need for analysis of natural populations with respect to how telomeres evolve.

Methodology/principal Findings: Here, we show that telomere length is heritable in free-ranging sand lizards, Lacerta agilis.

Sexual differences in telomere selection in the wild.

Telomere length is restored primarily through the action of the reverse transcriptase telomerase, which may contribute to a prolonged lifespan in some but not all species and may result in longer telomeres in one sex than the other. To what extent this is an effect of proximate mechanisms (e.g.

Proximate determinants of telomere length in sand lizards (Lacerta agilis).

Telomeres are repeat sequences of non-coding DNA that cap the ends of chromosomes and contribute to their stability and the genomic integrity of cells. In evolutionary ecology, the main research target regarding these genomic structures has been their role in ageing and as a potential index of age. However, research on humans shows that a number of traits contribute to among-individual differences in telomere length, in particular traits enhancing cell division and genetic erosion, such as levels of free radicals and stress.

Trapped in the extinction vortex? Strong genetic effects in a declining vertebrate population.

Background: Inbreeding and loss of genetic diversity are expected to increase the extinction risk of small populations, but detailed tests in natural populations are scarce. We combine long-term population and fitness data with those from two types of molecular markers to examine the role of genetic effects in a declining metapopulation of southern dunlins Calidris alpina schinzii, an endangered shorebird.

Results: The decline is associated with increased pairings between related individuals, including close inbreeding (as revealed by both field observations of parentage and molecular markers).

Age-independent telomere length predicts fitness in two bird species.

Telomeres are dynamic DNA-protein structures that form protective caps at the ends of eukaryotic chromosomes. Although initial telomere length is partly genetically determined, subsequent accelerated telomere shortening has been linked to elevated levels of oxidative stress. Recent studies show that short telomere length alone is insufficient to induce cellular senescence; advanced attrition of these repetitive DNA sequences does, however, reflect ageing processes.