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. Telomeres are the protective endcaps of chromosomes and their erosion with age is thought to play a crucial role in regulating organismal senescence and intrinsic lifespan. Following evidence that shorter telomeres may reduce the lifespan of animals in a wide range of taxa, we predict individuals with shorter telomeres to behave more boldly and aggressively. In order to test this, we measured telomere length and behaviour in wild juvenile brown trout (Salmo trutta). We found individuals with shorter fin telomeres to behave consistently more boldly and aggressively under controlled conditions in the laboratory. No such relationship was found with muscle telomere length 3–4 months after the behavioural assays. We suggest that telomere dynamics are an important factor integrating personality traits with other state variables thought to be important in the regulation of behaviour, such as metabolism, disease resistance and growth

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

<p>Abstract</p> <p>Background</p> <p>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 <it>Calidris alpina schinzii</it>, an endangered shorebird.</p> <p>Results</p> <p>The decline is associated with increased pairings between related individuals, including close inbreeding (as revealed by both field observations of parentage and molecular markers). Furthermore, reduced genetic diversity seems to affect individual fitness at several life stages. Higher genetic similarity between mates correlates negatively with the pair's hatching success. Moreover, offspring produced by related parents are more homozygous and suffer from increased mortality during embryonic development and possibly also after hatching.</p> <p>Conclusions</p> <p>Our results demonstrate strong genetic effects in a rapidly declining population, emphasizing the importance of genetic factors for the persistence of small populations.</p

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. However, strongly philopatric behaviour can reinforce relative isolation and the degree of genetic differentiation. The Southern Dunlin (Calidris alpina schinzii) is a philopatric, long-distance migratory shorebird and shows reduced dispersal between isolated breeding patches. The endangered population of the Southern Dunlin breeding at the Baltic Sea has suffered from habitat deterioration and fragmentation of coastal meadows. We sampled DNA across the entire population and used 12 polymorphic microsatellite loci to examine whether the environmental changes have resulted in genetic structuring and loss of variation. Results We found a pattern of isolation-by-distance across the whole Baltic population and genetic differentiation between local populations, even within the southern Baltic. Observed heterozygosity was lower than expected throughout the range and internal relatedness values were positive indicating inbreeding. Conclusions Our results provide long-term, empirical evidence for the theoretically expected links between habitat fragmentation, population subdivision, and gene flow. They also demonstrate a rare case of genetic differentiation between populations of a long-distance migratory species. The Baltic Southern Dunlin differs from many related shorebird species that show near panmixia, reflecting its philopatric life history and the reduced connectivity of its breeding patches. The results have important implications as they suggest that reduced connectivity of breeding habitats can threaten even long-distance migrants if they show strong philopatry during breeding. The Baltic Southern Dunlin warrants urgent conservation efforts that increase functional connectivity and gene flow between breeding areas.Peer reviewe

Genetic differentiation in an endangered and strongly philopatric, migrant shorebird

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. However, strongly philopatric behaviour can reinforce relative isolation and the degree of genetic differentiation. The Southern Dunlin (Calidris alpina schinzii) is a philopatric, long-distance migratory shorebird and shows reduced dispersal between isolated breeding patches. The endangered population of the Southern Dunlin breeding at the Baltic Sea has suffered from habitat deterioration and fragmentation of coastal meadows. We sampled DNA across the entire population and used 12 polymorphic microsatellite loci to examine whether the environmental changes have resulted in genetic structuring and loss of variation. </p

Sex Differences in Sand Lizard Telomere Inheritance: Paternal Epigenetic Effects Increases Telomere Heritability and Offspring Survival

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.Here, we show that telomere length is heritable in free-ranging sand lizards, Lacerta agilis. More importantly, heritability estimates analysed within, and contrasted between, the sexes are markedly different; son-sire heritability is much higher relative to daughter-dam heritability. We assess the effect of paternal age on Telomere Length (TL) and show that in this species, paternal age at conception is the best predictor of TL in sons. Neither paternal age per se at blood sampling for telomere screening, nor corresponding age in sons impact TL in sons. Processes maintaining telomere length are also associated with negative fitness effects, most notably by increasing the risk of cancer and show variation across different categories of individuals (e.g. males vs. females). We therefore tested whether TL influences offspring survival in their first year of life. Indeed such effects were present and independent of sex-biased offspring mortality and offspring malformations.TL show differences in sex-specific heritability with implications for differences between the sexes with respect to ongoing telomere selection. Paternal age influences the length of telomeres in sons and longer telomeres enhance offspring survival

Inavel och förlust av genetisk variation hos sydlig kärrsnäppa (Calidris alpina schinzii) på svenska Västkusten

Den sydliga kärrsnäppan har minskat kraftigt i antal inom stora delar av sitt utbredningsområde. I Sverige är rasen numera klassad som "starkt hotad". Biotopförluster i form av upphörd betesdrift och dränering av våtmarker, samt bopredation har identifierats som hot. Den svenska populationen av sydlig kärrsnäppa utgörs av ett antal relativt små och isolerade delbestånd, vilket även ökar risken för att populationen är utsatt för negativa effekter av genetisk drift och inavel (särskilt eftersom fåglarna är starkt hemortstrogna). I denna rapport presenteras för första gången en utvärdering av betydelsen av genetiska faktorer för beståndsutvecklingen. Befintliga populationsdata från en långtidsstudie på Västkusten har kombinerats med nya molekylärgenetiska resultat (baserade på två olika typer av genetiska markörer: DNA fingerprinting och mikrosatellitanalys).Beståndet på Västkusten har minskat sedan början av 1990-talet, trots aktiva skyddsåtgärder under senare år för att reducera bopredationen. Man fann att minskningen är associerad med en ökad frekvens av parningar mellan besläktade individer (inklusive incest), vilket speglar en förhöjd grad av släktskap i populationen. Man kunde också belägga att genetisk likhet mellan parmedlemmarna hade en negativ effekt på kläckningsframgången. Parningarna mellan besläktade individer gav upphov till ungar med reducerad genetisk variation, vilket resulterade i högre dödlighet såväl under fosterutvecklingen som efter kläckningen. Resultaten visar att populationen av sydlig kärrsnäppa på Västkusten är under stark påverkan av genetiska faktorer. Eftersom andra bestånd i landet troligen är utsatta för samma hot, bör betydelsen av genetiska faktorer och hur de kan motverkas inkluderas som en viktig faktor i åtgärdsprogrammet för att bevara den sydliga kärrsnäppan.Regionala inventeringsrapporter import från MDP 2015-05</p

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

<p>Abstract</p> <p>Background</p> <p>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. Using extensive longitudinal data from a long-term study of a natural population of barnacle geese <it>Branta leucopsis</it>, we investigated individual rates of telomere length changes over two years in 34 birds between 0 and 22 years of age, covering almost 80% of the species’ lifespan.</p> <p>Results</p> <p>We show that telomeres in this long-lived bird are very well maintained, as theoretically expected, with an average loss rate of only 5 base pairs per year among adults. We thus found no significant relationship between change in telomere length and age. However, telomeres tended to shorten at a faster pace in juveniles compared to adults. For the first time, we demonstrate a faster telomere attrition rate in females compared to males. We found no correlation between telomere loss rate and adult survival or change in body mass.</p> <p>Conclusions</p> <p>Our results add further support for a link between longevity and telomere maintenance, and highlight the complexities of telomere dynamics in natural populations.</p

Proximate determinants of telomere length in sand lizards ( References Subject collections 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. In lizards, tail loss owing to predation attempts results in a stress-induced shift to a more cryptic lifestyle. In sand lizard (Lacerta agilis) males, telomere length was compromised by tail regrowth in a body size-related manner, so that small males, which already exhibit more cryptic mating tactics, were less affected than larger males. Tail regrowth just fell short of having a significant relationship with telomere length in females, and so did age in males. In females, there was a significant positive relationship between age and telomere length. We conclude that the proximate effect of compromised antipredation and its associated stress seems to have a more pronounced effect in males than in females and that age-associated telomere dynamics differ between the sexes