50 research outputs found
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Implications of existing local (mal)adaptations for ecological forecasting under environmental change
Standing genetic variation represents a genetic load on population fitness but can also support a rapid response to shortâterm environmental change, and the greatest potential source of such standing genetic variation typically exists among locally adapted populations living along an environmental gradient. Here we develop a spatiallyâexplicitly simulation model to quantify the contribution of existing genetic variation arising from migrationâmutationâselectionâdrift balance to time to extinction under environmental change. Simulations reveal that local adaptation across a species range associated with an underlying environmental gradient could extend time to extinction by nearly threeâfold irrespective of the rate of environmental change. The potential for preâadapted alleles to increase the rate of adaptation changes the relative importance of established extinction risk factors, in particular it reduced the importance of the breadth of environmental tolerance and it increased the relative importance of fecundity. Although migration of preadapted alleles generally increased persistence time, it decreased it at rates of environmental change close to the critical rate of change by creating a population bottleneck, which ultimately limited the rate at which de novo mutations could arise. An analysis of the extinction dynamics further revealed that one consequence of gene flow is the potential to maximise population growth rate in at least part of the species range, which is likely to have consequences for forecasting the consequences of ecological interactions. Our study shows that predictions of persistence time change fundamentally when existing local adaptations are explicitly taken into account, underscoring the need to preserve and manage genetic diversity
Developmental Stability: A Major Role for Cyclin G in Drosophila melanogaster
Morphological consistency in metazoans is remarkable given the pervasive occurrence of genetic variation, environmental effects, and developmental noise. Developmental stability, the ability to reduce developmental noise, is a fundamental property of multicellular organisms, yet its genetic bases remains elusive. Imperfect bilateral symmetry, or fluctuating asymmetry, is commonly used to estimate developmental stability. We observed that Drosophila melanogaster overexpressing Cyclin G (CycG) exhibit wing asymmetry clearly detectable by sight. Quantification of wing size and shape using geometric morphometrics reveals that this asymmetry is a genuineâbut extremeâfluctuating asymmetry. Overexpression of CycG indeed leads to a 40-fold increase of wing fluctuating asymmetry, which is an unprecedented effect, for any organ and in any animal model, either in wild populations or mutants. This asymmetry effect is not restricted to wings, since femur length is affected as well. Inactivating CycG by RNAi also induces fluctuating asymmetry but to a lesser extent. Investigating the cellular bases of the phenotypic effects of CycG deregulation, we found that misregulation of cell size is predominant in asymmetric flies. In particular, the tight negative correlation between cell size and cell number observed in wild-type flies is impaired when CycG is upregulated. Our results highlight the role of CycG in the control of developmental stability in D. melanogaster. Furthermore, they show that wing developmental stability is normally ensured via compensatory processes between cell growth and cell proliferation. We discuss the possible role of CycG as a hub in a genetic network that controls developmental stability
Growth and Asymmetry of Soil Microfungal Colonies from âEvolution Canyon,â Lower Nahal Oren, Mount Carmel, Israel
Fluctuating asymmetry is a contentious indicator of stress in populations of animals and plants. Nevertheless, it is a measure of developmental noise, typically obtained by measuring asymmetry across an individual organism's left-right axis of symmetry. These individual, signed asymmetries are symmetrically distributed around a mean of zero. Fluctuating asymmetry, however, has rarely been studied in microorganisms, and never in fungi.We examined colony growth and random phenotypic variation of five soil microfungal species isolated from the opposing slopes of âEvolution Canyon,â Mount Carmel, Israel. This canyon provides an opportunity to study diverse taxa inhabiting a single microsite, under different kinds and intensities of abiotic and biotic stress. The south-facing âAfricanâ slope of âEvolution Canyonâ is xeric, warm, and tropical. It is only 200 m, on average, from the north-facing âEuropeanâ slope, which is mesic, cool, and temperate. Five fungal species inhabiting both the south-facing âAfricanâ slope, and the north-facing âEuropeanâ slope of the canyon were grown under controlled laboratory conditions, where we measured the fluctuating radial asymmetry and sizes of their colonies. from the âAfricanâ slope were more asymmetric than those from the âEuropeanâ slope.Our study suggests that fluctuating radial asymmetry has potential as an indicator of random phenotypic variation and stress in soil microfungi. Interaction of slope and species for both growth rate and asymmetry of microfungi in a common environment is evidence of genetic differences between the âAfricanâ and âEuropeanâ slopes of âEvolution Canyon.
Within-individual phenotypic plasticity in flowers fosters pollination niche shift
Authors thank Raquel SĂĄnchez, Angel Caravante, Isabel SĂĄnchez Almazo, Tatiana LĂłpez
PĂ©rez, Samuel Cantarero, MarĂa JosĂ© Jorquera and GermĂĄn FernĂĄndez for helping us during
several phases of the study and IvĂĄn RodrĂguez ArĂłs for drawing the insect silhouettes. This
research is supported by grants from the Spanish Ministry of Science, Innovation and
Universities (CGL2015-71634-P, CGL2015-63827-P, CGL2017-86626-C2-1-P, CGL2017-
86626-C2-2-P, UNGR15-CE-3315, including EU FEDER funds), Junta de AndalucĂa (P18-
FR-3641), Xunta de Galicia (CITACA), BBVA Foundation (PR17_ECO_0021), and a
contract grant to C.A. from the former Spanish Ministry of Economy and Competitiveness
(RYC-2012-12277). This is a contribution to the Research Unit Modeling Nature, funded by
the ConsejerĂa de EconomĂa, Conocimiento, Empresas y Universidad, and European
Regional Development Fund (ERDF), reference SOMM17/6109/UGR.Phenotypic plasticity, the ability of a genotype of producing different phenotypes when exposed to different environments, may impact ecological interactions. We study here how within-individual plasticity in Moricandia arvensis flowers modifies its pollination niche. During spring, this plant produces large, cross-shaped, UV-reflecting lilac flowers attracting mostly long-tongued large bees. However, unlike most co-occurring species, M. arvensis keeps flowering during the hot, dry summer due to its plasticity in key vegetative traits. Changes in temperature and photoperiod in summer trigger changes in gene expression and the production of small, rounded, UV-absorbing white flowers that attract a different assemblage of generalist pollinators. This shift in pollination niche potentially allows successful reproduction in harsh conditions, facilitating M. arvensis to face anthropogenic perturbations and climate change. Floral phenotypes impact interactions between plants and pollinators. Here, the authors show that Moricandia arvensis displays discrete seasonal plasticity in floral phenotype, with large, lilac flowers attracting long-tongued bees in spring and small, rounded, white flowers attracting generalist pollinators in summer.Spanish Ministry of Science, Innovation and Universities (EU FEDER funds)
CGL2015-71634-P
CGL2015-63827-P
CGL2017-86626-C2-1-P
CGL2017-86626-C2-2-P
UNGR15-CE-3315Junta de Andalucia
P18-FR-3641Xunta de GaliciaBBVA Foundation
PR17_ECO_0021Spanish Ministry of Economy and Competitiveness
RYC-2012-12277Consejeria de Economia, Conocimiento, Empresas y Universidad
SOMM17/6109/UGREuropean Union (EU)
SOMM17/6109/UG
Response to Packard: make sure we do not throw out the biological baby with the statistical bath water when performing allometric analyses
International audienc
Evolutionary allometry reveals a shift in selection pressure on male horn size
International audienc
Response to Packard: make sure we do not throw out the biological baby with the statistical bath water when performing allometric analyses
International audienc
Data from: Does multiple paternity affect seed mass in angiosperms? An experimental test in Dalechampia scandens
Flowers fertilized by multiple fathers may be expected to produce heavier seeds than those fertilized by a single father. However, the adaptive mechanisms leading to such differences remain unclear, and the evidence inconsistent. Here, we first review the different hypotheses predicting an increase in seed mass when multiple paternity occurs. We show that distinguishing between these hypotheses requires information about average seed mass, but also about within-fruit variance in seed mass, bias in siring success among pollen donors, and whether siring success and seed mass are correlated. We then report the results of an experiment on Dalechampia scandens (Euphorbiaceae), assessing these critical variables in conjunction with a comparison of seed mass resulting from crosses with single vs. multiple pollen donors. Siring success differed among males when competing for fertilization, but average seed mass was not affected by the number of fathers. Furthermore, paternal identity explained only 3.8% of the variance in seed mass, and siring success was not correlated with the mass of the seeds produced. Finally, within-infructescence variance in seed mass was not affected by the number of fathers. These results suggest that neither differential allocation nor sibling rivalry has any effect on the average mass of seeds in multiply sired fruits in D. scandens. Overall, the limited paternal effects observed in most studies and the possibility of diversification bet hedging among flowers (but not within flowers), suggest that multiple paternity within fruits or infructescence is unlikely to affect seed mass in a large number of angiosperm species