The 2014 Town and Community Profiles bring together information on more than 1000 Victorian communities from a wide variety of sources, both internal and external to the Department of Health and …Show full descriptionThe 2014 Town and Community Profiles bring together information on more than 1000 Victorian communities from a wide variety of sources, both internal and external to the Department of Health and Department of Human Services. The Profiles include information on population, geography, services and facilities, and social, cultural and demographic characteristics of each suburb, town and rural catchment in Victoria.

When estimating heritability in free-living populations, it is common practice to account for common environment effects, because of their potential to generate phenotypic covariance among relatives thereby biasing heritability estimates. In quantitative genetic studies of natural populations, however, philopatry, which results in relatives being clustered in space, is rarely accounted for. The two studies to have done so suggest absolute declines in heritability estimates of up to 43% when accounting for space sharing by relatives. However, due to methodological limitations these estimates may not be representative. We used data from the St. Kilda Soay sheep population to estimate heritabilities with and without accounting for space sharing for five traits for which there is evidence for additive genetic variance (birth weight, birth date, lamb August weight, and female post mortem jaw and metacarpal length). We accounted for space sharing by related females by separately incorporating spatial autocorrelation, and a home range similarity matrix. Although these terms accounted for up to 17% of the variance in these traits, heritability estimates were only reduced by up to 7%. Our results suggest that the bias caused by not accounting for space sharing may be lower than previously thought. This suggests that philopatry does not inevitably lead to a large bias if space sharing by relatives is not accounted for. We hope our work stimulates researchers to model shared space when relatives in their study population share space, as doing so will enable us to better understand when bias may be of particular concern.

The 2014 Town and Community Profiles bring together information on more than 1000 Victorian communities from a wide variety of sources, both internal and external to the Department of Health and Department of Human Services. The Profiles include information on population, geography, services and facilities, and social, cultural and demographic characteristics of each suburb, town and rural catchment in Victoria.

Dramatic local population decline brought about by anthropogenic-driven change is an increasingly common threat to biodiversity. Seabird life history traits that make them particularly vulnerable to such change, therefore understanding population connectivity and dispersal dynamics is vital for successful management. Our study used a 360 base-pair mitochondrial control region locus sequenced for 103 individuals and 18 nuclear microsatellite loci genotyped for 245 individuals to investigate population structure in the Atlantic and Pacific populations of the pelagic seabird, Leach's storm-petrel Oceanodroma leucorhoa leucorhoa. This species is under intense predation pressure at one regionally important colony on St Kilda, Scotland, where a disparity between population decline and predation rates hints at immigration from other large colonies. AMOVA, FST, ΦST and Bayesian cluster analyses revealed no genetic structure among Atlantic colonies (Global ΦST = -0.02 P >0.05, Global FST = 0.003, P>0.05, STRUCTURE K = 1), consistent with either contemporary gene flow or strong historical association within the ocean basin. The Pacific and Atlantic populations are genetically distinct (Global ΦST = 0.32 P <0.0001, Global FST = 0.04, P <0.0001, STRUCTURE K = 2), but evidence for inter-ocean exchange was found with individual exclusion/assignment and population coalescent analyses. These findings highlight the importance of conserving multiple colonies at a number of different sites and suggest that management of this seabird may be best viewed at an oceanic scale. Moreover, our study provides an illustration of how long-distance movement may ameliorate the potentially deleterious impacts of localised environmental change, although direct measures of dispersal are still required to better understand this process.

The estimation of quantitative genetic parameters in wild populations is generally limited by the accuracy and completeness of the available pedigree information. Using relatedness at genome-wide markers can potentially remove this limitation and lead to less biased and more precise estimates. We estimated heritability, maternal genetic effects and genetic correlations for body size traits in an unmanaged long-term study population of Soay sheep on St Kilda using three increasingly complete and accurate estimates of relatedness: (1) Pedigree 1, using observation-derived maternal links and microsatellite-derived paternal links; (2) Pedigree 2, using SNP-derived assignment of both maternity and paternity; and (3) whole-genome relatedness at 37,037 autosomal SNPs. In initial analyses, heritability estimates were strikingly similar for all three methods while standard errors were systematically lower in analyses based on Pedigree 2 and genomic relatedness. Genetic correlations were generally strong, differed little between the three estimates of relatedness and the standard errors declined only very slightly with improved relatedness information. When partitioning maternal effects into separate genetic and environmental components, maternal genetic effects found in juvenile traits increased substantially across the three relatedness estimates. Heritability declined compared to parallel models where only a maternal environment effect was fitted, suggesting that maternal genetic effects are confounded with direct genetic effects and that more accurate estimates of relatedness were better able to separate maternal genetic effects from direct genetic effects. We found that the heritability captured by SNP markers asymptoted at about half the SNPs available, suggesting that denser marker panels are not necessarily required for precise and unbiased heritability estimates. Finally, we present guidelines for the use of genomic relatedness in future quantitative genetics studies in natural populations.

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Life history trade-offs are ubiquitous across species and place constraints on the timing of life history events, including the optimal age at first reproduction. However, studies on lifetime breeding success of male mammals are rare due to sex-biased dispersal and the requirement for genetic paternity inferences. We studied the correlates and apparent fitness consequences of early-life reproduction among males in a free-living population of Soay sheep (Ovis aries) on St Kilda, Scotland. We investigated the factors associated with early breeding success and the apparent consequences of early success for survival and future reproduction. We used genetic paternity inferences, population data and individual morphology measurements collected over 30 years. We found that individuals born in years with low-density population size had the highest early-life breeding success, and singletons were more likely to be successful than twins. Individuals that bred successfully at seven months were mor...

How do environmental conditions influence selection and genetic variation in wild populations? There is widespread evidence for selection-by-environment interactions (S*E), but we reviewed studies of natural populations estimating the extent of genotype-by-environment interactions (G*E) in response to natural variation in environmental conditions, and found that evidence for G*E appears to be rare within single populations in the wild. Studies estimating the simultaneous impact of environmental variation on both selection and genetic variation are especially scarce. Here, we used 24 years of data collected from a wild Soay sheep population to quantify how an important environmental variable, population density, impacts upon (1) selection through annual contribution to fitness and (2) expression of genetic variation, in six morphological and life-history traits: body weight; hind leg length; parasite burden; horn length; horn growth; and testicular circumference. Our results supported the existence of S*E: selection was stronger in years of higher population density in all traits apart from horn growth, with directional selection being stronger under more adverse conditions. Quantitative genetic models revealed significant additive genetic variance for body weight, leg length, parasite burden, horn length and testes size, but not for horn growth or our measure of annual fitness. However, random regression models found variation between individuals in their responses to the environment in only three traits, and did not support the presence of G*E for any trait. Our analyses of St Kilda Soay sheep data thus concurs with our cross-study review that, while natural environmental variation within a population can profoundly alter the strength of selection on phenotypic traits, there is less evidence for its effect on the expression of genetic variance in the wild.