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Query: "keywords" (natural selection) .

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1.
Environmental determinants of interpopulation variation in chemical and visual signals in an insular lizard
Rodrigo Megía-Palma, Prem Aguilar, Anamarija Žagar, Marcio R. Pie, Urban Dajčman, Santiago Merino, Miguel A. Carretero, José Martín, 2026, research data

Abstract: Understanding how communication systems evolve across heterogeneous environments requires examining multiple signalling modalities. In 2017 and 2018, we examined geographic variation in chemical signals of the insular lizard Gallotia galloti across 16 sites on Tenerife (Canary Islands). We analysed interpopulation variation in the lipophilic fraction of male femoral gland secretions in relation to vegetation cover (NDVI), local sex ratio, ectoparasite load and macroclimatic factors. In 2023, we also analysed visual signals of two lizard phenotypes that occur in contrasting habitats of Tenerife. We modelled the chromatic and achromatic conspicuousness of colour patches under both a conspecific (lacertid) and an avian predator visual system to examine habitat-dependent divergence in signal detectability. Chemical signal diversity decreased with increasing shrub vegetation cover, while males from sites with male-biased sex ratios exhibited greater individual chemical richness, consistent with heightened intrasexual competition. Populations in xeric habitats and with higher mite loads showed relatively higher proportions of α-tocopherol, whereas greener habitats were associated with higher proportions of steroids. In contrast, visual analyses revealed that lizards from densely vegetated habitats exhibited greater chromatic conspicuousness and larger chromatic volumes, particularly under the conspecific visual model. Achromatic contrast showed weaker habitat-dependent differentiation, consistent with the hypothesis that luminance divergence is constrained by predator-mediated selection due to the high luminance sensitivity of avian visual systems. Thus, in open habitats, persistent and chemically diverse secretions may enhance communication efficiency under increased exposure, whereas in vegetated environments chromatic visual signals appear to be amplified, potentially driven by sexual selection while constrained by predation risk. These findings suggest that environmental heterogeneity can promote complementary divergence across signalling modalities, highlighting the importance of integrating sensory ecology and social context to understand the evolution of animal communication.
Keywords: animal communication, ecological gradients, Gallotia galloti, local adaptation, sexual versus natural selection
Published in DiRROS: 31.07.2026; Views: 246; Downloads: 165
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2.
Time-sampled population sequencing reveals the interplay of selection and genetic drift in experimental evolution of Potato virus Y
Denis Kutnjak, Santiago F. Elena, Maja Ravnikar, 2017, original scientific article

Abstract: RNA viruses are one of the fastest-evolving biological entities. Within their hosts, they exist as genetically diverse populations (i.e., viral mutant swarms), which are sculpted by different evolutionary mechanisms, such as mutation, natural selection, and genetic drift, and also the interactions between genetic variants within the mutant swarms. To elucidate the mechanisms that modulate the population diversity of an important plant-pathogenic virus, we performed evolution experiments with Potato virus Y (PVY) in potato genotypes that differ in their defense response against the virus. Using deep sequencing of small RNAs, we followed the temporal dynamics of standing and newly generated variations in the evolving viral lineages. A time-sampled approach allowed us to (i) reconstruct theoretical haplotypes in the starting population by using clustering of single nucleotide polymorphisms' trajectories and (ii) use quantitative population genetics approaches to estimate the contribution of selection and genetic drift, and their interplay, to the evolution of the virus. We detected imprints of strong selective sweeps and narrow genetic bottlenecks, followed by the shift in frequency of selected haplotypes. Comparison of patterns of viral evolution in differently susceptible host genotypes indicated possible diversifying evolution of PVY in the less-susceptible host (efficient in the accumulation of salicylic acid). IMPORTANCE High diversity of within-host populations of RNA viruses is an important aspect of their biology, since they represent a reservoir of genetic variants, which can enable quick adaptation of viruses to a changing environment. This study focuses on an important plant virus, Potato virus Y, and describes, at high resolution, temporal changes in the structure of viral populations within different potato genotypes. A novel and easy-to-implement computational approach was established to cluster single nucleotide polymorphisms into viral haplotypes from very short sequencing reads. During the experiment, a shift in the frequency of selected viral haplotypes was observed after a narrow genetic bottleneck, indicating an important role of the genetic drift in the evolution of the virus. On the other hand, a possible case of diversifying selection of the virus was observed in less susceptible host genotypes.
Keywords: Potato virus Y, experimental evolution, genetic drift, natural selection, sRNA deep sequencing
Published in DiRROS: 24.07.2024; Views: 1512; Downloads: 873
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