| 1. |
- Ahola, Virpi, et al.
(författare)
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The Glanville fritillary genome retains an ancient karyotype and reveals selective chromosomal fusions in Lepidoptera
- 2014
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5, s. 4737-
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies have reported that chromosome synteny in Lepidoptera has been well conserved, yet the number of haploid chromosomes varies widely from 5 to 223. Here we report the genome (393 Mb) of the Glanville fritillary butterfly (Melitaea cinxia; Nymphalidae), a widely recognized model species in metapopulation biology and eco-evolutionary research, which has the putative ancestral karyotype of n = 31. Using a phylogenetic analyses of Nymphalidae and of other Lepidoptera, combined with orthologue-level comparisons of chromosomes, we conclude that the ancestral lepidopteran karyotype has been n = 31 for at least 140 My. We show that fusion chromosomes have retained the ancestral chromosome segments and very few rearrangements have occurred across the fusion sites. The same, shortest ancestral chromosomes have independently participated in fusion events in species with smaller karyotypes. The short chromosomes have higher rearrangement rate than long ones. These characteristics highlight distinctive features of the evolutionary dynamics of butterflies and moths.
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| 2. |
- Fountain, Toby, et al.
(författare)
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Inferring dispersal across a fragmented landscape using reconstructed families in the Glanville fritillary butterfly
- 2018
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Ingår i: Evolutionary Applications. - : Wiley. - 1752-4571. ; 11:3, s. 287-297
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Tidskriftsartikel (refereegranskat)abstract
- Dispersal is important for determining both species ecological processes, such as population viability, and its evolutionary processes, like gene flow and local adaptation. Yet obtaining accurate estimates in the wild through direct observation can be challenging or even impossible, particularly over large spatial and temporal scales. Genotyping many individuals from wild populations can provide detailed inferences about dispersal. We therefore utilized genomewide marker data to estimate dispersal in the classic metapopulation of the Glanville fritillary butterfly (Melitaea cinxia L.), in the Åland Islands in SW Finland. This is an ideal system to test the effectiveness of this approach due to the wealth of information already available covering dispersal across small spatial and temporal scales, but lack of information at larger spatial and temporal scales. We sampled three larvae per larval family group from 3732 groups over a six-year period and genotyped for 272 SNPs across the genome. We used this empirical data set to reconstruct cases where full-sibs were detected in different local populations to infer female effective dispersal distance, that is, dispersal events directly contributing to gene flow. On average this was one kilometre, closely matching previous dispersal estimates made using direct observation. To evaluate our power to detect full-sib families, we performed forward simulations using an individual-based model constructed and parameterized for the Glanville fritillary metapopulation. Using these simulations, 100% of predicted full-sibs were correct and over 98% of all true full-sib pairs were detected. We therefore demonstrate that even in a highly dynamic system with a relatively small number of markers, we can accurately reconstruct full-sib families and for the first time make inferences on female effective dispersal. This highlights the utility of this approach in systems where it has previously been impossible to obtain accurate estimates of dispersal over both ecological and evolutionary scales.
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| 3. |
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| 4. |
- Gyllenberg, Mats, 1955-, et al.
(författare)
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Conditional reproductive strategies under variable environmental conditions
- 2017
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Ingår i: Annales Zoologici Fennici. - : Finnish Zoological and Botanical Publishing Board. - 0003-455X .- 1797-2450. ; 54:1-4, s. 193-204
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Tidskriftsartikel (refereegranskat)abstract
- Within the framework of adaptive dynamics we consider the evolution by natural selection of reproductive strategies in which individualsmay adjust their reproductive behaviour in response to changing environmental conditions. As a specific example we consider a discrete-time model in which possible fluctuations in the environmental conditions are caused by predator-prey interaction. Our main findings include: 1) Coexistence between two fixed strategies (i.e., strategies that do not adjust to changing environmental conditions) is impossible. There exists a best fixed strategy, which invades and ousts all other fixed strategies. 2) A necessary condition for conditional (adjustable) strategies to evolve is that there are fluctuations in the environmental conditions. Predator-prey interactions may cause such fluctuations and under natural assumptions there exists an optimal conditional strategy which is uninvadable and invades and ousts allother strategies.
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| 5. |
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| 6. |
- Gyllenberg, Mats, et al.
(författare)
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Single-species metapopulation dynamics : A structured model
- 1992
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Ingår i: Theoretical Population Biology. - 0040-5809 .- 1096-0325. ; 42:1, s. 35-61
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Tidskriftsartikel (refereegranskat)abstract
- We describe and analyse a general metapopulation model, which consists of a model of local dynamics within a habitat patch, and balance equations for dispersing individuals and the metapopulation. The model includes the effects of emigration and immigration on local dynamics. We derive the equilibrium population size distribution, which is skewed towards either small or large populations, depending on the relative magnitudes of local and metapopulation time scales. The model predicts a generally positive relationship between the fraction of occupied patches and the average local population size. Such a relationship has been commonly observed in nature. The model allows alternative stable equilibria, not found in models which ignore the effect of dispersal on local dynamics. We discuss the implications of our results for biological invasions and conservation biology
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| 7. |
- Nonaka, Etsuko, et al.
(författare)
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Scaling up the effects of inbreeding depression from individuals to metapopulations
- 2019
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 88:8, s. 1202-1214
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Tidskriftsartikel (refereegranskat)abstract
- Inbreeding is common in nature, and many laboratory studies have documented that inbreeding depression can reduce the fitness of individuals. Demonstrating the consequences of inbreeding depression on the growth and persistence of populations is more challenging because populations are often regulated by density- or frequency-dependent selection and influenced by demographic and environmental stochasticity. A few empirical studies have shown that inbreeding depression can increase extinction risk of local populations. The importance of inbreeding depression at the metapopulation level has been conjectured based on population-level studies but has not been evaluated. We quantified the impact of inbreeding depression affecting the fitness of individuals on metapopulation persistence in heterogeneous habitat networks of different sizes and habitat configuration in a context of natural butterfly metapopulations. We developed a spatial individual-based simulation model of metapopulations with explicit genetics. We used Approximate Bayesian Computation to fit the model to extensive demographic, genetic and life-history data available for the well-studied Glanville fritillary butterfly (Melitaea cinxia) metapopulations in the angstrom land islands in SW Finland. We compared 18 semi-independent habitat networks differing in size and fragmentation. The results show that inbreeding is more frequent in small habitat networks, and consequently, inbreeding depression elevates extinction risks in small metapopulations. Metapopulation persistence and neutral genetic diversity maintained in the metapopulations increase with the total habitat amount in and mean patch size of habitat networks. Dispersal and mating behaviour interact with landscape structure to determine how likely it is to encounter kin while looking for mates. Inbreeding depression can decrease the viability of small metapopulations even when they are strongly influenced by stochastic extinction-colonization dynamics and density-dependent selection. The findings from this study support that genetic factors, in addition to demographic factors, can contribute to extinctions of small local populations and also of metapopulations.
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| 8. |
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| 9. |
- Tack, Ayco J. M., et al.
(författare)
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Increasing frequency of low summer precipitation synchronizes dynamics and compromises metapopulation stability in the Glanville fritillary butterfly
- 2015
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 282:1806
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is known to shift species' geographical ranges, phenologies and abundances, but less is known about other population dynamic consequences. Here, we analyse spatio-temporal dynamics of the Glanville fritillary butterfly (Melitaea cinxia) in a network of 4000 dry meadows during 21 years. The results demonstrate two strong, related patterns: the amplitude of year-to-year fluctuations in the size of the metapopulation as a whole has increased, though there is no long-term trend in average abundance; and there is a highly significant increase in the level of spatial synchrony in population dynamics. The increased synchrony cannot be explained by increasing within-year spatial correlation in precipitation, the key environmental driver of population change, or in per capita growth rate. On the other hand, the frequency of drought during a critical life-history stage (early larval instars) has increased over the years, which is sufficient to explain the increasing amplitude and the expanding spatial synchrony in metapopulation dynamics. Increased spatial synchrony has the general effect of reducing long-term metapopulation viability even if there is no change in average metapopulation size. This study demonstrates how temporal changes in weather conditions can lead to striking changes in spatio-temporal population dynamics.
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| 10. |
- von Hertzen, Leena, et al.
(författare)
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Helsinki alert of biodiversity and health
- 2015
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Ingår i: Annals of Medicine. - : Informa UK Limited. - 1365-2060 .- 0785-3890. ; 47:3, s. 218-225
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Forskningsöversikt (refereegranskat)abstract
- Urban living in built environments, combined with the use of processed water and food, may not provide the microbial stimulation necessary for a balanced development of immune function. Many chronic inflammatory disorders, including allergic, autoimmune, metabolic, and even some behavioural disorders, are linked to alteration in the human commensal microbiota. Sedentary lifestyle is associated with reduced exposure to a broad spectrum of environmental micro-organisms and surplus energy balance, both risk factors of chronic inflammatory disorders. According to the Biodiversity Hypothesis, an environment with diverse macrobiota and microbiota modifies and enriches the human microbiota, which in turn is crucial in the development and maintenance of appropriate immune function. These issues were discussed in the symposium 'Chronic Inflammation, Lifestyle and Environment ', held in Helsinki, 20 - 22 August 2014, under the sponsorship of the Yrjo Jahnsson Foundation. This paper briefly outlines the recent findings in the context of the environment, lifestyle, and health; discusses the forces that undermine immune tolerance in urban environments; and highlights the possibilities to restore broken immune tolerance among urban dwellers, summarizing the main messages in four statements and calling for actions to combat major public health threats.
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