| 1. |
- Andrade, Pedro, et al.
(författare)
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Regulatory changes in pterin and carotenoid genes underlie balanced color polymorphisms in the wall lizard
- 2019
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 116:12, s. 5633-5642
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Tidskriftsartikel (refereegranskat)abstract
- Reptiles use pterin and carotenoid pigments to produce yellow, orange, and red colors. These conspicuous colors serve a diversity of signaling functions, but their molecular basis remains unresolved. Here, we show that the genomes of sympatric color morphs of the European common wall lizard (Podarcis muralis), which differ in orange and yellow pigmentation and in their ecology and behavior, are virtually undifferentiated. Genetic differences are restricted to two small regulatory regions near genes associated with pterin [sepiapterin reductase (SPR)] and carotenoid [beta-carotene oxygenase 2 (BCO2)] metabolism, demonstrating that a core gene in the housekeeping pathway of pterin biosynthesis has been coopted for bright coloration in reptiles and indicating that these loci exert pleiotropic effects on other aspects of physiology. Pigmentation differences are explained by extremely divergent alleles, and haplotype analysis revealed abundant transspecific allele sharing with other lacertids exhibiting color polymorphisms. The evolution of these conspicuous color ornaments is the result of ancient genetic variation and cross-species hybridization.
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| 2. |
- Botterill-James, Thomas, et al.
(författare)
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Experimental manipulation suggests effect of polyandry but not mate familiarity on within-pair aggression in the social skink, Liopholis whitii
- 2017
-
Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 71:4
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Long-term monogamy is a key characteristic of family living across animals. The evolutionary maintenance of long-term monogamy has been suggested to be facilitated by increased reproductive coordination as a result of mate familiarity, leading to increased reproductive success. However, such effects can be compromised if females mate outside the pair bond (e.g. female polyandry), introducing conflicts of interest between the male and female. Here, we experimentally test the effects of both mate familiarity and female polyandry on agonistic behaviour and reproduction in a family living lizard, Liopholis whitii. We found that mate familiarity did not decrease the level of aggression between pairs whereas reducing female polyandry did. However, we did not find an effect of either mate familiarity or female polyandry on female reproductive output. These results suggest that male behavioural responses to female polyandry may influence pair stability in Liopholis whitii, providing support for the growing appreciation of the multiple ways in which female polyandry can influence the stability of family living. Significance statement: Family living is underpinned by social pair bonds between adults (i.e. stable social monogamy). Therefore, key to understanding the emergence and maintenance of family living is identifying factors influencing pair bonds. We manipulated both female polyandry and mate familiarly in replicated enclosure experiment using social lizards to test their role in mediating within-pair aggression and ultimately the coordination of reproductive behaviour and hence reproductive output. We found that polyandry but not mate familiarity influenced levels of aggression between pairs but this did not transmit into concomitant effects on reproductive output.
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| 3. |
- Botterill-James, Thomas, et al.
(författare)
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Family aggression in a social lizard
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of family living is underpinned by conflict and cooperation between family members. While family groups can be maintained by reducing conflict between parents and offspring, interactions between siblings may play an equally important role. Here, we compared the level of aggressive interactions between siblings to that between parents and their offspring in the family living skink Liopholis whitii. Aggressive interactions occurred much more frequently between siblings and between fathers and offspring than between mothers and their offspring. These results suggest that ecological and social conditions that reduce conflict between siblings and between males and offspring will be fundamental in the evolutionary maintenance and diversification of family living in these lizards.
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| 4. |
- Cordero, Gerardo A., et al.
(författare)
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Physiological plasticity in lizard embryos exposed to high-altitude hypoxia
- 2017
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Ingår i: JOURNAL OF EXPERIMENTAL ZOOLOGY PART A-ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY. - : Wiley. - 2471-5646 .- 2471-5638. ; 327:7, s. 423-432
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Tidskriftsartikel (refereegranskat)abstract
- Coping with novel environments may be facilitated by plastic physiological responses that enable survival during environmentally sensitive life stages. We tested the capacity for embryos of the common wall lizard (Podarcis muralis) from low altitude to cope with low-oxygen partial pressure (hypoxia) in an alpine environment. Developing embryos subjected to hypoxic atmospheric conditions (15-16% O-2 sea-level equivalent) at 2,877m above sea level exhibited responses common to vertebrates acclimatized to or evolutionarily adapted to high altitude: suppressed metabolism, cardiac hypertrophy, and hyperventilation. These responses might have contributed to the unaltered incubation duration and hatching success relative to the ancestral, low-altitude, condition. Even so, hypoxia constrained egg energy utilization such that larger eggs produced hatchlings with relatively low mass. These findings highlight the role of physiological plasticity in maintaining fitness-relevant phenotypes in high-altitude environments, providing impetus to further explore altitudinal limits to ecological diversification in ectothermic vertebrates.
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| 5. |
- English, Sinead, et al.
(författare)
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Adaptive use of information during growth can explain long-term effects of early life experiences
- 2016
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Ingår i: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 187:5, s. 620-632
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Tidskriftsartikel (refereegranskat)abstract
- Development is a continuous process during which individuals gain information about their environment and adjust their phenotype accordingly. In many natural systems, individuals are particularly sensitive to early life experiences, even in the absence of later constraints on plasticity. Recent models have highlighted how the adaptive use of information can explain age-dependent plasticity. These models assume that information gain and phenotypic adjustments either cannot occur simultaneously or are completely independent. This assumption is not valid in the context of growth, where finding food results both in a size increase and learning about food availability. Here, we describe a simple model of growth to provide proof of principle that long-termeffects of early life experiences can arise through the coupled dynamics of information acquisition and phenotypic change in the absence of direct constraints on plasticity. The increase in reproductive value from gaining information and sensitivity of behavior to experiences declines across development. Early life experiences have longterm impacts on age of maturity, yet-due to compensatory changes in behavior-our model predicts no substantial effects on reproductive success. We discuss how the evolution of sensitive windows can be explained by experiences having short-term effects on informational and phenotypic states, which generate long-term effects on life-history decisions.
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| 6. |
- English, Sinead, et al.
(författare)
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Does early-life diet affect longevity? A meta-analysis across experimental studies
- 2016
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Ingår i: Biology letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 12:9
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Tidskriftsartikel (refereegranskat)abstract
- Life-history theory predicts that nutrition influences lifespan owing to tradeoffs between allocating resources to reproduction, growth and repair. Despite occasional reports that early diet has strong effects on lifespan, it is unclear whether this prediction is generally supported by empirical studies. We conducted a meta-analysis across experimental studies manipulating pre- or post-natal diet and measuring longevity. We found no overall effect of early diet on lifespan. We used meta-regression, considering moderator variables based on experimental and life-history traits, to test predictions regarding the strength and direction of effects that could lead to positive or negative effects. Pre-natal diet manipulations reduced lifespan, but there were no effects of later diet, manipulation type, development mode, or sex. The results are consistent with the prediction that early diet restriction disrupts growth and results in increased somatic damage, which incurs lifespan costs. Our findings raise a cautionary note, however, for placing too strong an emphasis on early diet effects on lifespan and highlight limitations of measuring these effects under laboratory conditions.
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| 7. |
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| 8. |
- English, Sinead, et al.
(författare)
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The information value of non-genetic inheritance in plants and animals.
- 2015
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Parents influence the development of their offspring in many ways beyond the transmission of DNA. This includes transfer of epigenetic states, nutrients, antibodies and hormones, and behavioural interactions after birth. While the evolutionary consequences of such non-genetic inheritance are increasingly well understood, less is known about how inheritance mechanisms evolve. Here, we present a simple but versatile model to explore the adaptive evolution of non-genetic inheritance. Our model is based on a switch mechanism that produces alternative phenotypes in response to different inputs, including genes and non-genetic factors transmitted from parents and the environment experienced during development. This framework shows how genetic and non-genetic inheritance mechanisms and environmental conditions can act as cues by carrying correlational information about future selective conditions. Differential use of these cues is manifested as different degrees of genetic, parental or environmental morph determination. We use this framework to evaluate the conditions favouring non-genetic inheritance, as opposed to genetic determination of phenotype or within-generation plasticity, by applying it to two putative examples of adaptive non-genetic inheritance: maternal effects on seed germination in plants and transgenerational phase shift in desert locusts. Our simulation models show how the adaptive value of non-genetic inheritance depends on its mechanism, the pace of environmental change, and life history characteristics.
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| 9. |
- Feiner, Nathalie, et al.
(författare)
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Developmental plasticity in reptiles: Insights from temperature-dependent gene expression in wall lizard embryos : Insights from temperature-dependent gene expression in wall lizard embryos
- 2018
-
Ingår i: Journal of experimental zoology. Part A, Ecological and integrative physiology. - : Wiley. - 2471-5638. ; 329:6-7, s. 351-361
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Tidskriftsartikel (refereegranskat)abstract
- Many features of the development of reptiles are affected by temperature, but very little is known about how incubation temperature affects gene expression. Here, we provide a detailed case study of gene expression profiles in common wall lizard (Podarcis muralis) embryos developing at stressfully low (15°C) versus benign (24°C) temperature. For maximum comparability between the two temperature regimes, we selected a precise developmental stage early in embryogenesis defined by the number of somites. We used a split-clutch design and lizards from four different populations to evaluate the robustness of temperature-responsive gene expression profiles. Embryos incubated at stressfully low incubation temperature expressed on average 20% less total RNA than those incubated at benign temperatures, presumably reflecting lower rates of transcription at cool temperature. After normalizing for differences in total amounts of input RNA, we find that approximately 50% of all transcripts show significant expression differences between the two incubation temperatures. Transcripts with the most extreme changes in expression profiles are associated with transcriptional and translational regulation and chromatin remodeling, suggesting possible epigenetic mechanisms underlying acclimation of early embryos to cool temperature. We discuss our findings in light of current advances in the use of transcriptomic data to study how individuals acclimatize and populations adapt to thermal stress.
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| 10. |
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| 11. |
- Feiner, Nathalie, et al.
(författare)
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Signatures of selection in embryonic transcriptomes of lizards adapting in parallel to cool climate
- 2018
-
Ingår i: Evolution. - : Wiley. - 0014-3820. ; 72:1, s. 67-81
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Tidskriftsartikel (refereegranskat)abstract
- Populations adapting independently to the same environment provide important insights into the repeatability of evolution at different levels of biological organization. In the 20th century, common wall lizards (Podarcis muralis) from southern and western Europe were introduced to England, north of their native range. Nonnative populations of both lineages have adapted to the shorter season and lower egg incubation temperature by increasing the absolute rate of embryonic development. Here, we tested if this adaptation is accompanied by signatures of directional selection in the transcriptomes of early embryos and, if so, if nonnative populations show adaptive convergence. Embryos from nonnative populations exhibited gene expression profiles consistent with directional selection following introduction, but different genes were affected in the two lineages. Despite this, the functional enrichment of genes that changed their expression following introduction showed substantial similarity between lineages, and was consistent with mechanisms that should promote developmental rate. Moreover, the divergence between nonnative and native populations was enriched for genes that were temperature-responsive in native populations. These results indicate that small populations are able to adapt to new climatic regimes, but the means by which they do so may largely be determined by founder effects and other sources of genetic drift.
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| 12. |
- Halliwell, Ben, et al.
(författare)
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Habitat saturation promotes delayed dispersal in a social reptile
- 2017
-
Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 28:2, s. 515-522
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Tidskriftsartikel (refereegranskat)abstract
- When and where offspring disperse has important implications for the evolutionary emergence and maintenance of group living. In noncooperative breeders, direct benefits of delayed dispersal are relatively limited, suggesting that decisions regarding whether or not to remain in the parental territory are largely driven by the availability of suitable habitat in which to settle. Although there is ample evidence of correlations between habitat saturation and delayed dispersal, experimental tests are rare, particularly for species with facultative group formation. We manipulated the density of conspecifics in enclosed populations of a family living reptile to experimentally evaluate the influence of habitat saturation on the tendency to delay dispersal. Habitat saturation did not influence whether or not offspring explored their surroundings. However, when conspecific density was high, more offspring delayed dispersal and those that did settle in high-density enclosures had reduced survival. These patterns appear to be due to increased dispersal costs imposed by conspecific aggression; offspring that explored high-density enclosures had reduced body condition and a greater risk of mortality. We discuss these results in the context of the evolutionary origins of family living.
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| 13. |
- Halliwell, Ben, et al.
(författare)
-
Live bearing promotes the evolution of sociality in reptiles
- 2017
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8:1
-
Tidskriftsartikel (refereegranskat)abstract
- Identifying factors responsible for the emergence and evolution of social complexity is an outstanding challenge in evolutionary biology. Here we report results from a phylogenetic comparative analysis of over 1000 species of squamate reptile, nearly 100 of which exhibit facultative forms of group living, including prolonged parent–offspring associations. We show that the evolution of social groupings among adults and juveniles is overwhelmingly preceded by the evolution of live birth across multiple independent origins of both traits. Furthermore, the results suggest that live bearing has facilitated the emergence of social groups that remain stable across years, similar to forms of sociality observed in other vertebrates. These results suggest that live bearing has been a fundamentally important precursor in the evolutionary origins of group living in the squamates.
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| 14. |
- Heathcote, Robert J P, et al.
(författare)
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Male behaviour drives assortative reproduction during the initial stage of secondary contact.
- 2016
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Ingår i: Journal of evolutionary biology. - : Wiley. - 1420-9101 .- 1010-061X. ; 29:5, s. 1003-1015
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Tidskriftsartikel (refereegranskat)abstract
- Phenotypic divergence in allopatry can facilitate speciation by reducing the likelihood that individuals of different lineages hybridise during secondary contact. However, few studies have established the causes of reproductive isolation in the crucial early stages of secondary contact. Here we establish behavioural causes of assortative reproduction between two phenotypically divergent lineages of the European wall lizard (Podarcis muralis), which have recently come into secondary contact. Parentage was highly assortative in experimental contact zones. However, despite pronounced divergence in male phenotypes, including chemical and visual sexual signals, there was no evidence that females discriminated between males of the two lineages in staged interactions or under naturalistic free-ranging conditions. Instead, assortative reproduction was driven by male mate preferences and, to a lesser extent, male-male competition. The effects were more pronounced when the habitat structure promoted high lizard densities. These results emphasize that assortative reproduction can occur in the absence of female choice, and that male behaviour may play an important role in limiting hybridisation during the initial stages of secondary contact. This article is protected by copyright. All rights reserved.
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| 15. |
- Laland, Kevin N, et al.
(författare)
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The extended evolutionary synthesis: its structure, assumptions and predictions.
- 2015
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Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 282:1813
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Forskningsöversikt (refereegranskat)abstract
- Scientific activities take place within the structured sets of ideas and assumptions that define a field and its practices. The conceptual framework of evolutionary biology emerged with the Modern Synthesis in the early twentieth century and has since expanded into a highly successful research program to explore the processes of diversification and adaptation. Nonetheless, the ability of that framework satisfactorily to accommodate the rapid advances in developmental biology, genomics and ecology has been questioned. We review some of these arguments, focusing on literatures (evo-devo, developmental plasticity, inclusive inheritance and niche construction) whose implications for evolution can be interpreted in two ways-one that preserves the internal structure of contemporary evolutionary theory and one that points towards an alternative conceptual framework. The latter, which we label the 'extended evolutionary synthesis' (EES), retains the fundaments of evolutionary theory, but differs in its emphasis on the role of constructive processes in development and evolution, and reciprocal portrayals of causation. In the EES, developmental processes, operating through developmental bias, inclusive inheritance and niche construction, share responsibility for the direction and rate of evolution, the origin of character variation and organism-environment complementarity. We spell out the structure, core assumptions and novel predictions of the EES, and show how it can be deployed to stimulate and advance research in those fields that study or use evolutionary biology.
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| 16. |
- Löwenborg Di Marino, Kristin, 1985-
(författare)
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Nesting ecology of the grass snake (Natrix natrix) and its implications for conservation
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The onset of agriculture about 12,000 years ago has had a major influence on the biodiversity of plants and animals. Unfortunately, the rapid changes in agricultural practices that has occurred in recent times has negatively affected many farmland species. One such species is the grass snake (Natrix natrix), which has been reported to decline in many parts of Europe, including Sweden. The grass snake is unique, not only in that it is the most northerly distributed oviparous reptile in the world, but also because of its habit of using anthropogenic heat sources such as manure heaps and composts as nesting-sites. Unfortunately changes in manure management and abandonment of farmlands have resulted in a decline and fragmentation of these environments. This may pose a threat for the northernmost populations of the grass snake, because natural nests in these areas may not provide sufficient heat for the eggs to hatch. The eggs and embryos of reptiles are highly sensitive to incubation temperatures, which can influence not only hatching success but also many phenotypic traits in the hatchlings. In this thesis I used a series of laboratory and field experiments to investigate the importance of anthropogenic heat sources for the reproductive ecology of cold-climate populations of grass snakes. More specifically, I aimed to investigate thermal regimes of nests and how they influence embryonic development and offspring traits associated with survival and fitness. The results showed that manure heaps and composts are significantly warmer than potential natural nests and that natural nests do not provide sufficient heat to sustain embryonic development. Further, manure heaps were warmer and more constant in temperature than composts, resulting in higher hatching success and earlier hatching in manure heaps. The higher thermal variability in composts increased the frequency of abnormalities that are likely to negatively affect survival and fitness. In conclusion, this thesis shows that the use of anthropogenic heat sources has enabled grass snakes to expand their range farther north than any other oviparous reptile and that the thermal dichotomy in the primary nesting environments used by grass snakes contribute to important life-history variation in this species. These findings have important implications for conservation of reptile populations in general and grass snakes in particular.
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| 17. |
- MacGregor, Hannah E A, et al.
(författare)
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Chemical communication, sexual selection, and introgression in wall lizards
- 2017
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Ingår i: Evolution. - : Wiley. - 0014-3820. ; 71:10, s. 2327-2343
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Tidskriftsartikel (refereegranskat)abstract
- Divergence in communication systems should influence the likelihood that individuals from different lineages interbreed, and consequently shape the direction and rate of hybridization. Here, we studied the role of chemical communication in hybridization, and its contribution to asymmetric and sexually selected introgression between two lineages of the common wall lizard (Podarcis muralis). Males of the two lineages differed in the chemical composition of their femoral secretions. Chemical profiles provided information regarding male secondary sexual characters, but the associations were variable and inconsistent between lineages. In experimental contact zones, chemical composition was weakly associated with male reproductive success, and did not predict the likelihood of hybridization. Consistent with these results, introgression of chemical profiles in a natural hybrid zone resembled that of neutral nuclear genetic markers overall, but one compound in particular (tocopherol methyl ether) matched closely the introgression of visual sexual characters. These results imply that associations among male chemical profiles, sexual characters, and reproductive success largely reflect transient and environmentally driven effects, and that genetic divergence in chemical composition is largely neutral. We therefore suggest that femoral secretions in wall lizards primarily provide information about residency and individual identity rather than function as sexual signals.
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| 18. |
- MacGregor, Hannah E A, et al.
(författare)
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Comparison of reproductive investment in native and non-native populations of common wall lizards reveals sex differences in adaptive potential
- 2017
-
Ingår i: Oikos. - : Wiley. - 0030-1299. ; 126:11, s. 1564-1574
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Tidskriftsartikel (refereegranskat)abstract
- Non-native animals can encounter very different environments than those they are adapted to. Functional changes in morphology, physiology and life-history following introduction show that organisms can adapt both fast and efficiently. It remains unclear, however, if female reproductive characters and male sexually selected behaviour show the same adaptive potential. Furthermore, the invasion success and evolutionary trajectory of non-native species might often depend on the ability of the sexes to coordinate shifts in characters associated with reproductive strategy. The common wall lizard, Podarcis muralis, has been repeatedly introduced from southern Europe to England over the past 80 years. Lizards in England experience a cool, seasonal climate that effectively restricts recruitment to the first clutch of the season, whereas in their native range up to three clutches per season recruit. As a consequence, both females and males in non-native populations should benefit from reducing or even eliminating their reproductive investment in second clutches. Using a combination of field data and experiments, we show that non-native females produce relatively larger and heavier first seasonal clutches and smaller and lighter second seasonal clutches compared to native females. In contrast, non-native and native males do not differ in their territorial and sexual behaviour later in the season. An adaptive shift in male seasonal reproductive investment may be constrained because males use breeding females as cues for sexual behaviour. If this is so, we expect a general pattern across climatic regimes whereby female reproductive investment evolves first, with responses in males lagging behind.
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| 19. |
- MacGregor, Hannah E A, et al.
(författare)
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Experimental contact zones reveal causes and targets of sexual selection in hybridizing lizards
- 2017
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 31:3, s. 742-752
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Tidskriftsartikel (refereegranskat)abstract
- Divergence in sexually selected traits in allopatry should affect the degree and direction of hybridization. However, few studies have established the causes and targets of sexual selection during secondary contact. Common wall lizards (Podarcis muralis) from north-central Italy have highly exaggerated male sexual traits compared to populations in Western Europe. Using experimental populations, we show that this creates asymmetries in male dominance, spatial habitat use and reproductive success upon secondary contact. Hybridization occurred almost exclusively between males of the Italian lineage and females of the Western European lineage. We provide evidence to suggest stronger ongoing selection on male sexual traits within the dominant Italian lineage. However, these same characters did not predict hybridization, and hybrid matings contributed little to variance in male reproductive success. Instead, most hybrid offspring were sired by Italian males displaying phenotypes associated with lower within-lineage reproductive success. Thus, highly directional hybridization arises because some Italian males are out-competed within their own lineage but remain competitive relative to males of the other lineage. This pattern of hybridization is consistent with the direction of introgression in natural contact zones, but our data suggest that sexual selection acting through hybridization may be weak at the leading edge of natural hybrid zones.
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| 20. |
- Michaelides, Sozos N., et al.
(författare)
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Loss of genetic diversity and increased embryonic mortality in non-native lizard populations
- 2016
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083. ; 25:17, s. 4113-4125
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Tidskriftsartikel (refereegranskat)abstract
- Many populations are small and isolated with limited genetic variation and high risk of mating with close relatives. Inbreeding depression is suspected to contribute to extinction of wild populations, but the historical and demographic factors that contribute to reduced population viability are often difficult to tease apart. Replicated introduction events in non-native species can offer insights into this problem because they allow us to study how genetic variation and inbreeding depression are affected by demographic events (e.g. bottlenecks), genetic admixture and the extent and duration of isolation. Using detailed knowledge about the introduction history of 21 non-native populations of the wall lizard Podarcis muralis in England, we show greater loss of genetic diversity (estimated from microsatellite loci) in older populations and in populations from native regions of high diversity. Loss of genetic diversity was accompanied by higher embryonic mortality in non-native populations, suggesting that introduced populations are sufficiently inbred to jeopardize long-term viability. However, there was no statistical correlation between population-level genetic diversity and average embryonic mortality. Similarly, at the individual level, there was no correlation between female heterozygosity and clutch size, infertility or hatching success, or between embryo heterozygosity and mortality. We discuss these results in the context of human-mediated introductions and how the history of introductions can play a fundamental role in influencing individual and population fitness in non-native species.
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| 21. |
- Michaelides, Sozos N., et al.
(författare)
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Widespread primary, but geographically restricted secondary, human introductions of wall lizards, Podarcis muralis
- 2015
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083. ; 24:11, s. 2702-2714
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Tidskriftsartikel (refereegranskat)abstract
- Establishing the introduction pathways of alien species is a fundamental task in invasion biology. The common wall lizard, Podarcis muralis, has been widely introduced outside of its native range in both Europe and North America, primarily through escaped pets or deliberate release of animals from captive or wild populations. Here, we use Bayesian clustering, approximate Bayesian computation (ABC) methods and network analyses to reconstruct the origin and colonization history of 23 non-native populations of wall lizards in England. Our analyses show that established populations in southern England originate from at least nine separate sources of animals from native populations in France and Italy. Secondary introductions from previously established non-native populations were supported for eleven (47%) populations. In contrast to the primary introductions, secondary introductions were highly restricted geographically and appear to have occurred within a limited time frame rather than being increasingly common. Together, these data suggest that extant wall lizard populations in England are the result of isolated accidental and deliberate releases of imported animals since the 1970s, with only local translocation of animals from established non-native populations. Given that populations introduced as recently as 25years ago show evidence of having adapted to cool climate, discouraging further translocations may be important to prevent more extensive establishment on the south coast of England.
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| 22. |
- Michaelides, Sozos, et al.
(författare)
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Phylogeography and conservation genetics of the common wall lizard, Podarcis muralis, on islands at its northern range.
- 2015
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- Populations at range limits are often characterized by lower genetic diversity, increased genetic isolation and differentiation relative to populations at the core of geographical ranges. Furthermore, it is increasingly recognized that populations situated at range limits might be the result of human introductions rather than natural dispersal. It is therefore important to document the origin and genetic diversity of marginal populations to establish conservation priorities. In this study, we investigate the phylogeography and genetic structure of peripheral populations of the common European wall lizard, Podarcis muralis, on Jersey (Channel Islands, UK) and in the Chausey archipelago. We sequenced a fragment of the mitochondrial cytochrome b gene in 200 individuals of P. muralis to infer the phylogeography of the island populations using Bayesian approaches. We also genotyped 484 individuals from 21 populations at 10 polymorphic microsatellite loci to evaluate the genetic structure and diversity of island and mainland (Western France) populations. We detected four unique haplotypes in the island populations that formed a sub-clade within the Western France clade. There was a significant reduction in genetic diversity (HO, HE and AR) of the island populations in relation to the mainland. The small fragmented island populations at the northern range margin of the common wall lizard distribution are most likely native, with genetic differentiation reflecting isolation following sea level increase approximately 7000 BP. Genetic diversity is lower on islands than in marginal populations on the mainland, potentially as a result of early founder effects or long-term isolation. The combination of restriction to specific localities and an inability to expand their range into adjacent suitable locations might make the island populations more vulnerable to extinction.
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| 23. |
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| 24. |
- Noble, Daniel W.A., et al.
(författare)
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Data Descriptor : A comprehensive database of thermal developmental plasticity in reptiles
- 2018
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Ingår i: Scientific Data. - : Springer Science and Business Media LLC. - 2052-4463. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- How temperature influences development has direct relevance to ascertaining the impact of climate change on natural populations. Reptiles have served as empirical models for understanding how the environment experienced by embryos can influence phenotypic variation, including sex ratio, phenology and survival. Such an understanding has important implications for basic eco-evolutionary theory and conservation efforts worldwide. While there is a burgeoning empirical literature of experimental manipulations of embryonic thermal environments, addressing widespread patterns at a comparative level has been hampered by the lack of accessible data in a format that is amendable to updates as new studies emerge. Here, we describe a database with nearly 10, 000 phenotypic estimates from 155 species of reptile, collected from 300 studies manipulating incubation temperature (published between 1974-2016). The data encompass various morphological, physiological, behavioural and performance traits along with growth rates, developmental timing, sex ratio and survival (e.g., hatching success). This resource will serve as an important data repository for addressing overarching questions about thermal plasticity of reptile embryos.
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| 25. |
- Noble, Daniel W.A., et al.
(författare)
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Plastic responses to novel environments are biased towards phenotype dimensions with high additive genetic variation
- 2019
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 116:27, s. 13452-13461
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Tidskriftsartikel (refereegranskat)abstract
- Environmentally induced phenotypes have been proposed to initiate and bias adaptive evolutionary change toward particular directions. The potential for this to happen depends in part on how well plastic responses are aligned with the additive genetic variance and covariance in traits. Using meta-analysis, we demonstrate that plastic responses to novel environments tend to occur along phenotype dimensions that harbor substantial amounts of additive genetic variation. This suggests that selection for or against environmentally induced phenotypes typically will be effective. One interpretation of the alignment between the direction of plasticity and the main axis of additive genetic variation is that developmental systems tend to respond to environmental novelty as they do to genetic mutation. This makes it challenging to distinguish if the direction of evolution is biased by plasticity or genetic “constraint.” Our results therefore highlight a need for new theoretical and empirical approaches to address the role of plasticity in evolution.
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| 26. |
- Paredes, Ursula, et al.
(författare)
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Low Incubation Temperature Induces DNA Hypomethylation in Lizard Brains
- 2016
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Ingår i: Journal of Experimental Zoology Part A: Ecological Genetics and Physiology. - : Wiley. - 1932-5223. ; 325:6, s. 390-395
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Tidskriftsartikel (refereegranskat)abstract
- Developmental stress can have organizational effects on suites of physiological, morphological, and behavioral characteristics. In lizards, incubation temperature is perhaps the most significant environmental variable affecting embryonic development. Wall lizards (Podarcis muralis) recently introduced by humans from Italy to England experience stressfully cool incubation conditions, which we here show reduce growth and increase the incidence of scale malformations. Using a methylation-sensitive AFLP protocol optimized for vertebrates, we demonstrate that this low incubation temperature also causes hypomethylation of DNA in brain tissue. A consistent pattern across methylation-susceptible AFLP loci suggests that hypomethylation is a general response and not limited to certain CpG sites. The functional consequences of hypomethylation are unknown, but it could contribute to genome stability and regulation of gene expression. Further studies of the effects of incubation temperature on DNA methylation in ectotherm vertebrates may reveal mechanisms that explain why the embryonic thermal environment often has physiological and behavioral consequences for offspring.
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| 27. |
- Radersma, Reinder, et al.
(författare)
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Timing of maternal exposure to toxic cyanobacteria and offspring fitness in Daphnia magna : Implications for the evolution of anticipatory maternal effects
- 2018
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 8:24, s. 12727-12736
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Tidskriftsartikel (refereegranskat)abstract
- Organisms that regularly encounter stressful environments are expected to use cues to develop an appropriate phenotype. Water fleas (Daphnia spp.) are exposed to toxic cyanobacteria during seasonal algal blooms, which reduce growth and reproductive investment. Because generation time is typically shorter than the exposure to cyanobacteria, maternal effects provide information about the local conditions subsequent generations will experience. Here, we evaluate if maternal effects in response to microcystin, a toxin produced by cyanobacteria, represent an inheritance system evolved to transmit information in Daphnia magna. We exposed mothers as juveniles and/or as adults, and tested the offspring's fitness in toxic and non-toxic environments. Maternal exposure until reproduction reduced offspring fitness, both in the presence and in the absence of toxic cyanobacteria. However, this effect was accompanied by a small positive fitness effect, relative to offspring from unexposed mothers, in the presence of toxic cyanobacteria. This effect was mainly elicited in response to maternal exposure to toxic cyanobacteria early in life and less so during reproduction. None of these effects were explained by changes in egg size. A meta-analysis using our and others’ experiments suggests that the adaptive value of maternal effects to cyanobacteria exposure is weak at best. We suggest that the beneficial maternal effect in our study is an example of phenotypic accommodation spanning generations, rather than a mechanism evolved to transmit information about cyanobacteria presence between generations.
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| 28. |
- Rago, Alfredo, et al.
(författare)
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How adaptive plasticity evolves when selected against
- 2019
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Ingår i: PLoS Computational Biology. - : Public Library of Science (PLoS). - 1553-7358. ; 15:3
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Tidskriftsartikel (refereegranskat)abstract
- Adaptive plasticity allows organisms to cope with environmental change, thereby increasing the population's long-term fitness. However, individual selection can only compare the fitness of individuals within each generation: if the environment changes more slowly than the generation time (i.e., a coarse-grained environment) a population will not experience selection for plasticity even if it is adaptive in the long-term. How does adaptive plasticity then evolve? One explanation is that, if competing alleles conferring different degrees of plasticity persist across multiple environments, natural selection between genetic lineages could select for adaptive plasticity (lineage selection). We show that adaptive plasticity can evolve even in the absence of such lineage selection. Instead, we propose that adaptive plasticity in coarse-grained environments evolves as a by-product of inefficient short-term natural selection: populations that rapidly evolve their phenotypes in response to selective pressures follow short-term optima, with the result that they have reduced long-term fitness across environments. Conversely, populations that accumulate limited genetic change within each environment evolve long-term adaptive plasticity even when plasticity incurs short-term costs. These results remain qualitatively similar regardless of whether we decrease the efficiency of natural selection by increasing the rate of environmental change or decreasing mutation rate, demonstrating that both factors act via the same mechanism. We demonstrate how this mechanism can be understood through the concept of learning rate. Our work shows how plastic responses that are costly in the short term, yet adaptive in the long term, can evolve as a by-product of inefficient short-term selection, without selection for plasticity at either the individual or lineage level.
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| 29. |
- Tobi, Elmar W., et al.
(författare)
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Selective Survival of Embryos Can Explain DNA Methylation Signatures of Adverse Prenatal Environments
- 2018
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 25:10, s. 4-2667
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Tidskriftsartikel (refereegranskat)abstract
- An adverse intrauterine environment is associated with long-term physiological changes in offspring. These are believed to be mediated by epigenomic marks, including DNA methylation (DNAm). Changes in DNAm are often interpreted as damage or plastic responses of the embryo. Here, we propose that stochastic DNAm variation, generated during remodeling of the epigenome after fertilization, contributes to DNAm signatures of prenatal adversity through differential survival of embryos. Using a mathematical model of re-methylation in the early embryo, we demonstrate that selection, but not plasticity, will generate a characteristic reduction in DNAm variance at loci that contribute to survival. Such a reduction in DNAm variance was apparent in a human cohort prenatally exposed to the Dutch famine, illustrating that it is possible to detect a signature of selection on epigenomic variation. Selection should be considered as a possible mechanism linking prenatal adversity to subsequent health and may have implications when evaluating interventions. Tobi et al. hypothesize that prenatal adversity can cause selection on epigenomic profiles in utero. Their model predicts that such selection reduces the variance in DNA methylation at genomic regions that contribute to survival, which is testable and detectable in empirical data from the Dutch famine.
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| 30. |
- Uller, Tobias, et al.
(författare)
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Developmental bias and evolution : A regulatory network perspective
- 2018
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Ingår i: Genetics. - : Oxford University Press (OUP). - 0016-6731 .- 1943-2631. ; 209:4, s. 949-966
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Tidskriftsartikel (refereegranskat)abstract
- Phenotypic variation is generated by the processes of development, with some variants arising more readily than others—a phenomenon known as“developmental bias.”Developmental bias and natural selection have often been portrayed as alternative explanations, but this is a false dichotomy: developmental bias can evolve through natural selection, and bias and selection jointly influence phenotypic evolution. Here, we briefly review the evidence for developmental bias and illustrate how it is studied empirically. We describe recent theory on regulatory networks that explains why the influence of genetic and environmental perturbation on phenotypes is typically not uniform, and may even be biased toward adaptive phenotypic variation. We show how bias produced by developmental processes constitutes an evolving property able to impose direction on adaptive evolution and influence patterns of taxonomic and phenotypic diversity. Taking these considerations together, we argue that it is not sufficient to accommodate developmental bias into evolutionary theory merely as a constraint on evolutionary adaptation. The influence of natural selection in shaping developmental bias, and conversely, the influence of developmental bias in shaping subsequent opportunities for adaptation, requires mechanistic models of development to be expanded and incorporated into evolutionary theory. A regulatory network perspective on phenotypic evolution thus helps to integrate the generation of phenotypic variation with natural selection, leaving evolutionary biology better placed to explain how organisms adapt and diversify.
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| 31. |
- Uller, Tobias, et al.
(författare)
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Genetic differentiation predicts body size divergence between island and mainland populations of common wall lizards (Podarcis muralis)
- 2019
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 127:4, s. 771-786
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Tidskriftsartikel (refereegranskat)abstract
- Small-bodied vertebrates sometimes evolve gigantism on islands, but there is a lack of consistent association with ecological factors or island characteristics. One possible reason is that, even if the ecological conditions are right, body size might fail to diverge on islands that were isolated recently or if there is gene flow between islands and the mainland. We studied body size, ventral colour polymorphism and genetic structure across nine islands and adjacent mainland populations of common wall lizards (Podarcis muralis) off the western coast of France. Population genetic data suggested that island populations might have maintained gene flow after their geographical isolation from the mainland. Island lizards were larger and heavier than mainland lizards on average, but the extent of gigantism varied substantially between islands. Island size and distance from the mainland were poor predictors of body size, but lizards from populations that were highly genetically differentiated from the mainland were larger than lizards from less differentiated populations. Colour morphs that were rare on the mainland tended to be more common on islands. We propose that genetic isolation or bottlenecks promote body size evolution in island lizards, which makes it challenging to identify ecological causes of island gigantism without complementary genetic information.
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| 32. |
- Uller, Tobias, et al.
(författare)
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When is incomplete epigenetic resetting in germ cells favoured by natural selection?
- 2015
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Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 1471-2954 .- 0962-8452. ; 282:1811
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Tidskriftsartikel (refereegranskat)abstract
- Resetting of epigenetic marks, such as DNA methylation, in germ cells or early embryos is not always complete. Epigenetic states may therefore persist, decay or accumulate across generations. In spite of mounting empirical evidence for incomplete resetting, it is currently poorly understood whether it simply reflects stochastic noise or plays an adaptive role in phenotype determination. Here, we use a simple model to show that incomplete resetting can be adaptive in heterogeneous environments. Transmission of acquired epigenetic states prevents mismatched phenotypes when the environment changes infrequently relative to generation time and when maternal and environmental cues are unreliable. We discuss how these results may help to interpret the emerging data on transgenerational epigenetic inheritance in plants and animals.
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| 33. |
- van den Heuvel, Joost, et al.
(författare)
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Disposable Soma Theory and the Evolution of Maternal Effects on Ageing.
- 2016
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Maternal effects are ubiquitous in nature and affect a wide range of offspring phenotypes. Recent research suggests that maternal effects also contribute to ageing, but the theoretical basis for these observations is poorly understood. Here we develop a simple model to derive expectations for (i) if maternal effects on ageing evolve; (ii) the strength of maternal effects on ageing relative to direct environmental effects; and (iii) the predicted relationships between environmental quality, maternal age and offspring lifespan. Our model is based on the disposable soma theory of ageing, and the key assumption is thus that mothers trade off their own somatic maintenance against investment in offspring. This trade-off affects the biological age of offspring at birth in terms of accumulated damage, as indicated by biomarkers such as oxidative stress or telomere length. We find that the optimal allocation between investment in maternal somatic investment and investment in offspring results in old mothers and mothers with low resource availability producing offspring with reduced life span. Furthermore, the effects are interactive, such that the strongest maternal age effects on offspring lifespan are found under low resource availability. These findings are broadly consistent with results from laboratory studies investigating the onset and rate of ageing and field studies examining maternal effects on ageing in the wild.
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| 34. |
- Waggoner, Miranda R., et al.
(författare)
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Epigenetic determinism in science and society
- 2015
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Ingår i: New Genetics and Society. - : Informa UK Limited. - 1463-6778 .- 1469-9915. ; 34:2, s. 177-195
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Tidskriftsartikel (refereegranskat)abstract
- The epigenetic "revolution" in science cuts across many disciplines, and it is now one of the fastest-growing research areas in biology. Increasingly, claims are made that epigenetics research represents a move away from the genetic determinism that has been prominent both in biological research and in understandings of the impact of biology on society. We discuss to what extent an epigenetic framework actually supports these claims. We show that, in contrast to the received view, epigenetics research is often couched in language as deterministic as genetics research in both science and the popular press. We engage the rapidly emerging conversation about the impact of epigenetics on public discourse and scientific practice, and we contend that the notion of epigenetic determinism - or the belief that epigenetic mechanisms determine the expression of human traits and behaviors - matters for understandings of the influence of biology and society on population health.
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| 35. |
- While, Geoffrey M, et al.
(författare)
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Adaptive responses to cool climate promotes persistence of a non-native lizard.
- 2015
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Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 282:1803
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Tidskriftsartikel (refereegranskat)abstract
- Successful establishment and range expansion of non-native species often require rapid accommodation of novel environments. Here, we use common-garden experiments to demonstrate parallel adaptive evolutionary response to a cool climate in populations of wall lizards (Podarcis muralis) introduced from southern Europe into England. Low soil temperatures in the introduced range delay hatching, which generates directional selection for a shorter incubation period. Non-native lizards from two separate lineages have responded to this selection by retaining their embryos for longer before oviposition-hence reducing the time needed to complete embryogenesis in the nest-and by an increased developmental rate at low temperatures. This divergence mirrors local adaptation across latitudes and altitudes within widely distributed species and suggests that evolutionary responses to climate can be very rapid. When extrapolated to soil temperatures encountered in nests within the introduced range, embryo retention and faster developmental rate result in one to several weeks earlier emergence compared with the ancestral state. We show that this difference translates into substantial survival benefits for offspring. This should promote short- and long-term persistence of non-native populations, and ultimately enable expansion into areas that would be unattainable with incubation duration representative of the native range.
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| 36. |
- While, Geoffrey M., et al.
(författare)
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Egernia lizards
- 2015
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Ingår i: Current Biology. - : Elsevier BV. - 1879-0445 .- 0960-9822. ; 25:14, s. 593-595
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 37. |
- While, Geoffrey M, et al.
(författare)
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Female reproductive investment in response to male phenotype in wall lizards and its implications for introgression
- 2017
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 121:4, s. 876-882
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Tidskriftsartikel (refereegranskat)abstract
- The likelihood that females will breed or how much they invest in reproduction can depend on the characters of their male partners. Such differential allocation may enhance or limit gene flow between hybridizing lineages, in particular when the lineages have diverged in sexually selected characters. Populations of the common wall lizard (Podarcis muralis) in some regions of Italy exhibit striking exaggeration of coloration, morphology and behaviour compared to populations in France. The two forms hybridize in north-western Italy. Gene flow is directional and in concordance with the prediction that the exaggerated sexual characters of lizards of Italian origin give them a mating advantage. To evaluate if differential allocation contributes to asymmetric introgression, we tested experimentally if female reproductive investment is affected by male origin and male secondary sexual characters. Despite the large genetic and phenotypic divergence between males of Italian and French origin, females did not invest more when paired with males of the same origin, nor when paired with males with highly expressed sexual characters. Combined, these results suggest that female responses to male phenotypes in wall lizards are unimportant for explaining the directional pattern of gene flow in regions of secondary contact.
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| 38. |
- While, Geoffrey M., et al.
(författare)
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Patterns of developmental plasticity in response to incubation temperature in reptiles
- 2018
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Ingår i: Journal of Experimental Zoology Part A: Ecological and Integrative Physiology. - : Wiley. - 2471-5638 .- 2471-5646. ; 329:4-5, s. 162-176
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Tidskriftsartikel (refereegranskat)abstract
- Early life environments shape phenotypic development in important ways that can lead to long-lasting effects on phenotype and fitness. In reptiles, one aspect of the early environment that impacts development is temperature (termed 'thermal developmental plasticity'). Indeed, the thermal environment during incubation is known to influence morphological, physiological, and behavioral traits, some of which have important consequences for many ecological and evolutionary processes. Despite this, few studies have attempted to synthesize and collate data from this expansive and important body of research. Here, we systematically review research into thermal developmental plasticity across reptiles, structured around the key papers and findings that have shaped the field over the past 50 years. From these papers, we introduce a large database (the 'Reptile Development Database') consisting of 9,773 trait means across 300 studies examining thermal developmental plasticity. This dataset encompasses data on a range of phenotypes, including morphological, physiological, behavioral, and performance traits along with growth rate, incubation duration, sex ratio, and survival (e.g., hatching success) across all major reptile clades. Finally, from our literature synthesis and data exploration, we identify key research themes associated with thermal developmental plasticity, important gaps in empirical research, and demonstrate how future progress can be made through targeted empirical, meta-analytic, and comparative work.
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| 39. |
- While, Geoffrey M, et al.
(författare)
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Sexual selection drives asymmetric introgression in wall lizards.
- 2015
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X. ; 18:12, s. 1366-1375
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Hybridisation is increasingly recognised as an important cause of diversification and adaptation. Here, we show how divergence in male secondary sexual characters between two lineages of the common wall lizard (Podarcis muralis) gives rise to strong asymmetries in male competitive ability and mating success, resulting in asymmetric hybridisation upon secondary contact. Combined with no negative effects of hybridisation on survival or reproductive characters in F1-hybrids, these results suggest that introgression should be asymmetric, resulting in the displacement of sexual characters of the sub-dominant lineage. This prediction was confirmed in two types of secondary contact, across a natural contact zone and in two introduced populations. Our study illustrates how divergence in sexually selected traits via male competition can determine the direction and extent of introgression, contributing to geographic patterns of genetic and phenotypic diversity.
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| 40. |
- Yang, Weizhao, et al.
(författare)
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Genomic evidence for asymmetric introgression by sexual selection in the common wall lizard
- 2018
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083.
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Tidskriftsartikel (refereegranskat)abstract
- Strongly selected characters can be transferred from one lineage to another with limited genetic exchange, resulting in asymmetric introgression and a mosaic genome in the receiving population. However, systems are rarely sufficiently well studied to link the pattern of introgression to its underlying process. Male common wall lizards in western Italy exhibit exaggeration of a suite of sexually selected characters that make them outcompete males from a distantly related lineage that lack these characters. This results in asymmetric hybridization and adaptive introgression of the suite of characters following secondary contact. We developed genomewide markers to infer the demographic history of gene flow between different genetic lineages, identify the spread of the sexually selected syndrome, and test the prediction that introgression should be asymmetric and heterogeneous across the genome. Our results show that secondary contact was accompanied by gene flow in both directions across most of the genome, but with approximately 3% of the genome showing highly asymmetric introgression in the predicted direction. Demographic simulations reveal that this asymmetric gene flow is more recent than the initial secondary contact, and the data suggest that the exaggerated male sexual characters originated within the Italian lineage and subsequently spread throughout this lineage before eventually reaching the contact zone. These results demonstrate that sexual selection can cause a suite of characters to spread throughout both closely and distantly related lineages with limited gene flow across the genome at large.
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