| 1. |
- 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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| 2. |
- 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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| 3. |
- 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
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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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| 4. |
- 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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| 5. |
- Bouffet-Halle, Alix, et al.
(författare)
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Characterisation and cross-amplification of sex-specific genetic markers in Australasian Egerniinae lizards and their implications for understanding the evolution of sex determination and social complexity
- 2022
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Ingår i: Australian Journal of Zoology. - 0004-959X. ; 69:2, s. 33-40
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Tidskriftsartikel (refereegranskat)abstract
- Sex is a pervasive factor that underpins functional phenotypic variation across a range of traits. Although sex can usually be distinguished morphologically, in some species this is not possible. The development of genetic markers for sex identification is, thus, key if we are to incorporate sex into an understanding of ecological or evolutionary process. Here we develop genetic markers for the identification of sex within an iconic Australian lizard group, the Egernia group, which is notable for its complex social behaviour. We used restriction-site associated DNA sequencing to characterise sex-specific genetic sequences for a key member of the group, Liopholis whitii, and designed primers for four of these putative sex-specific sequences. These primers amplified across some, but not all, species of the group. Our results provided several important insights. They suggest conservatism of a XX/XY sex determination system within the group as well as sex-specific genomic regions that appear independent of the conserved genomic regions identified in other skink species. More broadly, the development of sex markers for the Egernia group opens up a range of potential research questions related to the role that sex plays in the mediation of social behaviour and, through this, the emergence and stability of social life.
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| 6. |
- Feiner, Nathalie, et al.
(författare)
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Adaptive introgression reveals the genetic basis of a sexually selected syndrome in wall lizards
- 2024
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 10:14
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Tidskriftsartikel (refereegranskat)abstract
- The joint expression of particular colors, morphologies, and behaviors is a common feature of adaptation, but the genetic basis for such "phenotypic syndromes" remains poorly understood. Here, we identified a complex genetic architecture associated with a sexually selected syndrome in common wall lizards, by capitalizing on the adaptive introgression of coloration and morphology into a distantly related lineage. Consistent with the hypothesis that the evolution of phenotypic syndromes in vertebrates is facilitated by developmental linkage through neural crest cells, most of the genes associated with the syndrome are involved in neural crest cell regulation. A major locus was a similar to 400-kb region, characterized by standing structural genetic variation and previously implied in the evolutionary innovation of coloration and beak size in birds. We conclude that features of the developmental and genetic architecture contribute to maintaining trait integration, facilitating the extensive and rapid introgressive spread of suites of sexually selected characters.
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| 7. |
- 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
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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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| 8. |
- Feiner, Nathalie, et al.
(författare)
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Signatures of selection in embryonic transcriptomes of lizards adapting in parallel to cool climate
- 2018
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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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| 9. |
- Halliwell, Ben, et al.
(författare)
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Habitat saturation promotes delayed dispersal in a social reptile
- 2017
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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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| 10. |
- Halliwell, Ben, et al.
(författare)
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Live bearing promotes the evolution of sociality in reptiles
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8:1
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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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