Browsing by Subject "diet specialization"

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  • Vizueta, Joel; Macias-Hernandez, Nuria; Arnedo, Miguel A.; Rozas, Julio; Sanchez-Gracia, Alejandro (2019)
    The coexistence of multiple eco-phenotypes in independently assembled communities makes island adaptive radiations the ideal framework to test convergence and parallelism in evolution. In the radiation of the spider genus Dysdera in the Canary Islands, species diversification occurs concomitant with repeated events of trophic specialization. These dietary shifts, to feed primarily on woodlice, are accompanied by modifications in morphology (mostly in the mouthparts), behaviour and nutritional physiology. To gain insight into the molecular basis of this adaptive radiation, we performed a comprehensive comparative transcriptome analysis of five Canary Island Dysdera endemics representing two evolutionary and geographically independent events of dietary specialization. After controlling for the potential confounding effects of hemiplasy, our differential gene expression and selective constraint analyses identified a number of genetic changes that could be associated with the repeated adaptations to specialized diet of woodlice, including some related to heavy metal detoxification and homeostasis, the metabolism of some important nutrients and venom toxins. Our results shed light on the genomic basis of an extraordinary case of dietary shift convergence associated with species diversification. We uncovered putative molecular substrates of convergent evolutionary changes at different hierarchical levels, including specific genes, genes with equivalent functions and even particular amino acid positions. This study improves our knowledge of rapid adaptive radiations and provides new insights into the predictability of evolution.
  • Aykanat, Tutku; Rasmussen, Martin; Ozerov, Mikhail; Niemelä, Eero; Paulin, Lars; Vähä, Juha-Pekka; Hindar, Kjetil; Wennevik, Vidar; Pedersen, Torstein; Svenning, Martin-A.; Primmer, Craig R. (2020)
    1. Animals employ various foraging strategies along their ontogeny to acquire energy, and with varying degree of efficiencies, to support growth, maturation and subsequent reproduction events. Individuals that can efficiently acquire energy early are more likely to mature at an earlier age, as a result of faster energy gain which can fuel maturation and reproduction. 2. We aimed to test the hypothesis that heritable resource acquisition variation that covaries with efficiency along the ontogeny would influence maturation timing of individuals. 3. To test this hypothesis, we utilized Atlantic salmon as a model which exhibits a simple, hence trackable, genetic control of maturation age. We then monitored the variation in diet acquisition (quantified as stomach fullness and composition) of individuals with different ages, and linked it with genomic regions (haploblocks) that were previously identified to be associated with age-at-maturity. 4. Consistent with the hypothesis, we demonstrated that one of the life-history genomic regions tested (six6) was indeed associated with age-dependent differences in stomach fullness. Prey composition was marginally linked tosix6, and suggestively (but non-significantly) tovgll3genomic regions. We further showed Atlantic salmon switched to the so-called 'feast and famine' strategy along the ontogeny, where older age groups exhibited heavier stomach content, but that came at the expense of running on empty more often. 5. These results suggest genetic variation underlying resource utilization may explain the genetic basis of age structure in Atlantic salmon. Given that ontogenetic diet has a genetic component and the strong spatial diversity associated with these genomic regions, we predict populations with diverse maturation age will have diverse evolutionary responses to future changes in marine food web structures.
  • Aykanat, Tutku; Rasmussen, Martin; Ozerov, Mikhail; Niemelä, Eero; Paulin, Lars; Vähä, Juha-Pekka; Hindar, Kjetil; Wennevik, Vidar; Pedersen, Torstein; Svenning, Martin-A.; Primmer, Craig R. (2020)
    1. Animals employ various foraging strategies along their ontogeny to acquire energy, and with varying degree of efficiencies, to support growth, maturation and subsequent reproduction events. Individuals that can efficiently acquire energy early are more likely to mature at an earlier age, as a result of faster energy gain which can fuel maturation and reproduction. 2. We aimed to test the hypothesis that heritable resource acquisition variation that covaries with efficiency along the ontogeny would influence maturation timing of individuals. 3. To test this hypothesis, we utilized Atlantic salmon as a model which exhibits a simple, hence trackable, genetic control of maturation age. We then monitored the variation in diet acquisition (quantified as stomach fullness and composition) of individuals with different ages, and linked it with genomic regions (haploblocks) that were previously identified to be associated with age-at-maturity. 4. Consistent with the hypothesis, we demonstrated that one of the life-history genomic regions tested (six6) was indeed associated with age-dependent differences in stomach fullness. Prey composition was marginally linked tosix6, and suggestively (but non-significantly) tovgll3genomic regions. We further showed Atlantic salmon switched to the so-called 'feast and famine' strategy along the ontogeny, where older age groups exhibited heavier stomach content, but that came at the expense of running on empty more often. 5. These results suggest genetic variation underlying resource utilization may explain the genetic basis of age structure in Atlantic salmon. Given that ontogenetic diet has a genetic component and the strong spatial diversity associated with these genomic regions, we predict populations with diverse maturation age will have diverse evolutionary responses to future changes in marine food web structures.