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1.
S. Eryn McFarlane Jamieson C. Gorrell David W. Coltman Murray M. Humphries Stan Boutin Andrew G. McAdam 《Ecology and evolution》2014,4(10):1729-1738
A trait must genetically correlate with fitness in order to evolve in response to natural selection, but theory suggests that strong directional selection should erode additive genetic variance in fitness and limit future evolutionary potential. Balancing selection has been proposed as a mechanism that could maintain genetic variance if fitness components trade off with one another and has been invoked to account for empirical observations of higher levels of additive genetic variance in fitness components than would be expected from mutation–selection balance. Here, we used a long‐term study of an individually marked population of North American red squirrels (Tamiasciurus hudsonicus) to look for evidence of (1) additive genetic variance in lifetime reproductive success and (2) fitness trade‐offs between fitness components, such as male and female fitness or fitness in high‐ and low‐resource environments. “Animal model” analyses of a multigenerational pedigree revealed modest maternal effects on fitness, but very low levels of additive genetic variance in lifetime reproductive success overall as well as fitness measures within each sex and environment. It therefore appears that there are very low levels of direct genetic variance in fitness and fitness components in red squirrels to facilitate contemporary adaptation in this population. 相似文献
2.
The capacity of a population to adapt to selection (evolvability) depends on whether the structure of genetic variation permits the evolution of fitter trait combinations. Selection, genetic variance and genetic covariance can change under environmental stress, and males and females are not genetically independent, yet the combined effects of stress and dioecy on evolvability are not well understood. Here, we estimate selection, genetic (co)variance and evolvability in both sexes of Tribolium castaneum flour beetles under stressful and benign conditions, using a half‐sib breeding design. Although stress uncovered substantial latent heritability, stress also affected genetic covariance, such that evolvability remained low under stress. Sexual selection on males and natural selection on females favoured a similar phenotype, and there was positive intersex genetic covariance. Consequently, sexual selection on males augmented adaptation in females, and intralocus sexual conflict was weak or absent. This study highlights that increased heritability does not necessarily increase evolvability, suggests that selection can deplete genetic variance for multivariate trait combinations with strong effects on fitness, and tests the recent hypothesis that sexual conflict is weaker in stressful or novel environments. 相似文献
3.
Peter R. Grant B. Rosemary Grant 《Evolution; international journal of organic evolution》1994,48(2):297-316
Morphological consequences of hybridization were studied in a group of three interbreeding species of Darwin's finches on the small Galápagos island of Daphne Major in the inclusive years 1976 to 1992. Geospiza fortis bred with G. scandens and G. fuliginosa. Although interbreeding was always rare (< 5%), sufficient samples of measurements of hybrids and backcrosses were accumulated for analysis. Five beak and body dimensions and mass were measured, and from these two synthetic (principal-component) traits were constructed. All traits were heritable in two of the interbreeding species (G. fuliginosa were too rare to be analyzed) and in the combined samples of F, hybrids and backcrosses to G. fortis. In agreement with expectations from a model of polygenic inheritance, hybrid and backcross classes were generally phenotypically intermediate between the breeding groups that had produced them. Hybridization increased additive genetic and environmental variances, increased heritabilities to a moderate extent, and generally strengthened phenotypic and genetic correlations. New additive genetic variance introduced by hybridization is estimated to be two to three orders of magnitude greater than that introduced by mutation. Enhanced variation facilitates directional evolutionary change, subject to constraints arising from genetic correlations between characters. The Darwin's finch data suggest that these constraints become stronger when species with similar proportions hybridize, but some become weaker when the interbreeding species have different allometries. This latter effect of hybridization, together with an enhancement of genetic variation, facilitates evolutionary change in a new direction. 相似文献
4.
Predicting the impacts of climate change requires knowledge of the potential to adapt to rising temperatures, which is unknown for most species. Adaptive potential may be especially important in tropical species that have narrow thermal ranges and live close to their thermal optimum. We used the animal model to estimate heritability, genotype by environment interactions and nongenetic maternal components of phenotypic variation in fitness‐related traits in the coral reef damselfish, Acanthochromis polyacanthus. Offspring of wild‐caught breeding pairs were reared for two generations at current‐day and two elevated temperature treatments (+1.5 and +3.0 °C) consistent with climate change projections. Length, weight, body condition and metabolic traits (resting and maximum metabolic rate and net aerobic scope) were measured at four stages of juvenile development. Additive genetic variation was low for length and weight at 0 and 15 days posthatching (dph), but increased significantly at 30 dph. By contrast, nongenetic maternal effects on length, weight and body condition were high at 0 and 15 dph and became weaker at 30 dph. Metabolic traits, including net aerobic scope, exhibited high heritability at 90 dph. Furthermore, significant genotype x environment interactions indicated potential for adaptation of maximum metabolic rate and net aerobic scope at higher temperatures. Net aerobic scope was negatively correlated with weight, indicating that any adaptation of metabolic traits at higher temperatures could be accompanied by a reduction in body size. Finally, estimated breeding values for metabolic traits in F2 offspring were significantly affected by the parental rearing environment. Breeding values at higher temperatures were highest for transgenerationally acclimated fish, suggesting a possible role for epigenetic mechanisms in adaptive responses of metabolic traits. These results indicate a high potential for adaptation of aerobic scope to higher temperatures, which could enable reef fish populations to maintain their performance as ocean temperatures rise. 相似文献
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6.
B. ROGELL M. HOFMAN M. EKLUND A. LAURILA J. HÖGLUND 《Journal of evolutionary biology》2009,22(11):2267-2277
The potential to adapt to novel environmental conditions is a key area of interest for evolutionary biology. However, the role of multiple selection pressures on adaptive responses has rarely been investigated in natural populations. In Sweden, the natterjack toad Bufo calamita inhabits two separate distribution areas, one in southernmost Sweden and one on the west coast. We characterized the larval habitat in terms of pond size and salinity in the two areas, and found that the western populations are more affected by both desiccation risk and pond salinity than the southern populations. In a common garden experiment manipulating salinity and temperature, we found that toads from the west coast populations were locally adapted to shorter pond duration as indicated by their higher development and growth rates. However, despite being subjected to higher salinity stress in nature, west coast toads had a poorer performance in saline treatments. We found that survival in the saline treatments in the west coast populations was positively affected by larger body mass and longer larval period. Furthermore, we found negative genetic correlations between body mass and growth rate and their plastic responses to salinity. These results implicate that the occurrence of multiple environmental stressors needs to be accounted for when assessing the adaptive potential of organisms and suggest that genetic correlations may play a role in constraining adaptation of natural populations. 相似文献
7.
Shannon L. J. Bayliss Zoë R. Scott Mary Alice Coffroth Casey P. terHorst 《Ecology and evolution》2019,9(5):2803-2813
Symbionts within the family Symbiodiniaceae are important on coral reefs because they provide significant amounts of carbon to many different reef species. The breakdown of this mutualism that occurs as a result of increasingly warmer ocean temperatures is a major threat to coral reef ecosystems globally. Recombination during sexual reproduction and high rates of somatic mutation can lead to increased genetic variation within symbiont species, which may provide the fuel for natural selection and adaptation. However, few studies have asked whether such variation in functional traits exists within these symbionts. We used several genotypes of two closely related species, Breviolum antillogorgium and B. minutum, to examine variation of traits related to symbiosis in response to increases in temperature or nitrogen availability in laboratory cultures. We found significant genetic variation within and among symbiont species in chlorophyll content, photosynthetic efficiency, and growth rate. Two genotypes showed decreases in traits in response to increased temperatures predicted by climate change, but one genotype responded positively. Similarly, some genotypes within a species responded positively to high‐nitrogen environments, such as those expected within hosts or eutrophication associated with global change, while other genotypes in the same species responded negatively, suggesting context‐dependency in the strength of mutualism. Such variation in traits implies that there is potential for natural selection on symbionts in response to temperature and nutrients, which could confer an adaptive advantage to the holobiont. 相似文献
8.
Belinda van Heerwaarden Carla M. Sgrò 《Proceedings. Biological sciences / The Royal Society》2014,281(1790)
Species with restricted distributions make up the vast majority of biodiversity. Recent evidence suggests that Drosophila species with restricted tropical distributions lack genetic variation in the key trait of desiccation resistance. It has therefore been predicted that tropically restricted species will be limited in their evolutionary response to future climatic changes and will face higher risks of extinction. However, these assessments have been made using extreme levels of desiccation stress (less than 10% relative humidity (RH)) that extend well beyond the changes projected for the wet tropics under climate change scenarios over the next 30 years. Here, we show that significant evolutionary responses to less extreme (35% RH) but more ecologically realistic levels of climatic change and desiccation stress are in fact possible in two species of rainforest restricted Drosophila. Evolution may indeed be an important means by which sensitive rainforest-restricted species are able to mitigate the effects of climate change. 相似文献
9.
Lutz Becks Stephen P. Ellner Laura E. Jones Nelson G. Hairston Jr 《Ecology letters》2010,13(8):989-997
10.
Shannon Dillon Rachel McEvoy Darren S. Baldwin Simon Southerton Cherie Campbell Yvonne Parsons Gavin N. Rees 《Austral ecology》2015,40(5):558-572
The river red gum (Eucalyptus camaldulensis Dehnh.) inhabits riparian zones and associated floodplains throughout Australia. Following changes to hydrological regime due to river regulation and prolonged drought in south‐eastern Australia, river red gum populations within the Murray–Darling Basin have suffered substantial decline. To better understand the effect of drought on river red gum genetic diversity, we examined single nucleotide polymorphism (SNP) variation in 12 candidate genes among six red gum floodplain forest sites in Yanga National Park, which had experienced contrasting levels of drought and associated decline over an eight‐year period. We also examined genetic diversity using these markers in five additional river red gum populations from the Murray–Darling Basin to place genetic diversity results from Yanga in a regional context. Tree condition was significantly lower and mortality higher in the most drought affected sites; however, differences in overall genetic diversity and divergence were not detected among sites. No evidence of genetic adaptation in response to drought in this set of candidate genes was detected when differentiation at individual SNP loci was examined. While the overall condition of E. camaldulensis was strongly influenced by hydrological regime, our results suggest the evolutionary potential of floodplain forests in Yanga were not immediately impacted by population decline linked with drought and changes in hydrological regime. We propose that due to low genetic structure among populations in the region, genetic diversity of river red gums within the Murray–Darling Basin might be effectively conserved during periods of extended drought by protecting representative populations. 相似文献
11.
生物多样性是人类生存与发展的基础,全球气候的快速波动正对生物多样性造成严重威胁。保护生物学旨在研究全球生物多样性面临的危机及如何更加有效地进行生物多样性保护。景观基因组学（Landscape genomics）研究通过解析基因型与环境因子之间的关联性,揭示物种响应气候变化的适应性遗传变异与适应性进化,推动了保护生物学的快速发展。本文简要阐述了景观基因组学解析物种适应性遗传变异空间分布格局的主要研究方法,总结了近年来景观基因组学方法在动植物保护研究中的应用案例,并针对景观基因组学方法在保护生物学研究中存在的问题及未来研究方向提出了建议。 相似文献
12.
Evatt Chirgwin Keyne Monro Carla M. Sgro Dustin J. Marshall 《Global Change Biology》2015,21(9):3356-3366
The extent to which global change will impact the long‐term persistence of species depends on their evolutionary potential to adapt to future conditions. While the number of studies that estimate the standing levels of adaptive genetic variation in populations under predicted global change scenarios is growing all the time, few studies have considered multiple environments simultaneously and even fewer have considered evolutionary potential in multivariate context. Because conditions will not be constant, adaptation to climate change is fundamentally a multivariate process so viewing genetic variances and covariances over multivariate space will always be more informative than relying on bivariate genetic correlations between traits. A multivariate approach to understanding the evolutionary capacity to cope with global change is necessary to avoid misestimating adaptive genetic variation in the dimensions in which selection will act. We assessed the evolutionary capacity of the larval stage of the marine polychaete Galeolaria caespitosa to adapt to warmer water temperatures. Galeolaria is an important habitat‐forming species in Australia, and its earlier life‐history stages tend to be more susceptible to stress. We used a powerful quantitative genetics design that assessed the impacts of three temperatures on subsequent survival across over 30 000 embryos across 204 unique families. We found adaptive genetic variation in the two cooler temperatures in our study, but none in the warmest temperature. Based on these results, we would have concluded that this species has very little capacity to evolve to the warmest temperature. However, when we explored genetic variation in multivariate space, we found evidence that larval survival has the potential to evolve even in the warmest temperatures via correlated responses to selection across thermal environments. Future studies should take a multivariate approach to estimating evolutionary capacity to cope with global change lest they misestimate a species’ true adaptive potential. 相似文献
13.
《Insect Conservation and Diversity》2018,11(3):294-304
- Parnassius apollo filabricus is a subspecies of apollo (Lepidoptera, Papilionidae) restricted to the Sierra de Baza‐Filabres range in southeastern Spain that has become increasingly rare in the last decades, disappearing from most of its known locations.
- In this article, we calculate both census and effective population size of a local population discovered in 2009 that occupies c. 30 ha.
- After 2 years of capture–mark–recapture work we estimate a population size of about 100 individuals.
- Genetic variation was characterised using 9 microsatellite markers and 29 individuals. Effective population size was estimated from 13 microsatellites. The studied population is strongly differentiated from the nearby Sierra Nevada apollo populations, and its expected heterozygosity and allelic richness were higher than the average value for Sierra Nevada.
- Genetic diversity of the population is not as low as expected by its small size, which points out to a recent population decline. We discuss the implications of these results for the conservation of the species.
14.
Dolph Schluter James N. M. Smith 《Biological journal of the Linnean Society. Linnean Society of London》1986,29(1):23-36
We estimated heritabilities, and genetic and phenotypic correlations between beak and body traits in the song sparrow ( Melospiza melodia ). We compared these estimates to values for the same traits in the Galápagos finches, Geospiza (Boag, 1983; Grant, 1983). Morphological variance is low in the song sparrow, and our results show that genetic and phenotypic correlations are considerably lower than correlations in the morphologically more variable Geospiza. Comparison using a larger sample of Galapagos populations confirms the existence of an association between variance and correlation for phenotypic values. We suggest two possible explanations for this association. First, most traits studied are functionally related, and the joint evolution of variance and correlation may have resulted from stabilizing selection about a line of optimal allometry between traits. Alternatively, introgression between populations and species could have caused correlation and variance to evolve jointly. Both selection and introgression were probably influential in producing the observed pattern, but it is not possible to estimate their relative importance with current data. Genetic and phenotypic correlations were correlated in the song sparrow, but heritabilities of traits varied greatly. As a result, the genetic variance-covariance matrix for traits is not simply a constant multiple of the phenotypic matrix. Evolutionary response to natural selection cannot, therefore, be predicted from the measurement of phenotypic characteristics alone. 相似文献
15.
110000 years of Quaternary beetle diversity change 总被引：1，自引：0，他引：1
P. Ponel J. Orgeas M.J. Samways V. Andrieu-Ponel J.-L. de Beaulieu M. Reille P. Roche T. Tatoni 《Biodiversity and Conservation》2003,12(10):2077-2089
Our first aim was to document the effects of palaeotemperatures and vegetation changes on beetle assemblages, and secondly to determine the extent to which surrogacy analysis at the family taxonomic level reveals patterns evident from lower taxa analysis. The sedimentary sequence sampled on the experimental site of La Grande Pile (Vosges, France) covers the whole of the last climatic cycle. Beetle fragments were extracted from 39 coring samples and identified to the lowest possible taxonomic level. A total of 3092 beetle specimens belonging to 394 taxa were identified, more than half to species level. Carabidae, Staphylinidae and Curculionidae families together represented 40% of the overall taxa richness. Beetle taxa richness and assemblage composition varied markedly over time. Average summer temperatures clearly play a major role in diversity patterns, as temperature was positively correlated with taxon richness. Nevertheless, the warmest and the coldest periods were not the richest and the poorest, respectively, and the most humid period did not correspond to maximum beetle richness. Beetle assemblages are likely to fluctuate in response to other factors such as plant diversity and vegetation structure. Steppe-like vegetation did not reduce species richness while dense, homogenous and closed forests did. Family patterns mirrored those observed at the lower taxa level. This makes the family level a convincing alternative to lower taxonomic level analyses by representing a faithful picture of changing beetle diversity over a long period of time. Finally, evolution of beetle diversity over the Quaternary represents a convincing model for evaluating the effect of close and wide past climate changes, and for assisting in management of present-day biodiversity as part of the current anthropogenic global climate change. 相似文献
16.
Implications of varying pipe model relationships on Scots Pine growth in different climates 总被引：5，自引：0，他引：5
1. The process-based model SIMFORG , based on the pipe theory, was parameterized for Scots Pine at six locations along a north–south gradient in Europe. The ratio of foliage mass to stem cross-sectional area was changed as a function of potential evapotranspiration as proposed by Berninger et al. (1995).
2. Allocation to the stem differed between the locations and affected consequently the stemwood production. Variation in the net primary production and differences in the pipe model parameters were responsible for these differences. There was good agreement between measured and simulated data.
3. Increase in primary production, as predicted by climate-change senarios, increased allocation to the stem. However, the results were sensitive to changes in the foliage mass to stem sapwood cross-sectional area ratio. The changes in allocation were higher in the north than in the south. 相似文献
2. Allocation to the stem differed between the locations and affected consequently the stemwood production. Variation in the net primary production and differences in the pipe model parameters were responsible for these differences. There was good agreement between measured and simulated data.
3. Increase in primary production, as predicted by climate-change senarios, increased allocation to the stem. However, the results were sensitive to changes in the foliage mass to stem sapwood cross-sectional area ratio. The changes in allocation were higher in the north than in the south. 相似文献
17.
STEFAN SAFER KARIN TREMETSBERGER YAN‐PING GUO GUDRUN KOHL MARY R. SAMUEL TOD F. STUESSY HERMANN STUPPNER 《Botanical journal of the Linnean Society. Linnean Society of London》2011,165(4):364-377
The genus Leontopodium comprises 30–41 species. The centre of diversity is the Sino‐Himalayan region in south‐western China, where about 15 species occur. The two species native to Europe, L. alpinum (known as the common ‘Edelweiss’) and L. nivale, are part of the cultural heritage of the people living there. Despite its importance, very little is known about the systematics of the genus. Because recent molecular studies have shown that species within this genus are closely related and difficult to distinguish with rDNA and cpDNA data, we used AFLPs to obtain a more detailed understanding of the phylogeny of the genus. Our main aims were as follows: (1) to clarify species relationships within the genus; and (2) to reveal information about the biogeography of the genus. We used AFLPs with six primer combinations to investigate 216 individuals in 38 populations of 16 different species. With AFLPs, we were able to recognize 10 different groups, all of which had strong bootstrap support. These results were also congruent with the morphology‐based taxonomy of the genus. Most private and rare fragments were found in the Yunnan region (south‐western China) relative to Europe and Mongolia/central China, suggesting a long‐lasting in situ history of populations in the centre of diversity of the genus. Our results illustrate the utility of AFLPs to resolve phylogenetic relationships between these closely related species. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 165 , 364–377. 相似文献
18.
Evolutionary insights from studies of geographic variation: Contemporary variation and looking to the future 
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下载免费PDF全文 Julie R. Etterson Heather E. Schneider Jennifer J. Weber 《American journal of botany》2016,103(1):5-9
In an age of rapid global change, it is imperative that we continue to improve our understanding of factors that govern genetic differentiation in plants to inform biologically reasonable predictions for the future and enlighten conservation and restoration practices. In this special issue, we have assembled a set of original research and reviews that employ diverse approaches, both classic and contemporary, to illuminate patterns of phenotypic and genetic variation, probe the underlying evolutionary processes that have contributed to these patterns, build predictive models, and test evolutionary hypotheses. Our goal was to underscore the unique insights that can be obtained through the complementary and distinct studies of plant populations across species' geographic ranges. 相似文献
19.
Achyut Aryal Uttam Babu Shrestha Weihong Ji Som B. Ale Sujata Shrestha Tenzing Ingty Tek Maraseni Geoff Cockfield David Raubenheimer 《Ecology and evolution》2016,6(12):4065-4075
Future climate change is likely to affect distributions of species, disrupt biotic interactions, and cause spatial incongruity of predator–prey habitats. Understanding the impacts of future climate change on species distribution will help in the formulation of conservation policies to reduce the risks of future biodiversity losses. Using a species distribution modeling approach by MaxEnt, we modeled current and future distributions of snow leopard (Panthera uncia) and its common prey, blue sheep (Pseudois nayaur), and observed the changes in niche overlap in the Nepal Himalaya. Annual mean temperature is the major climatic factor responsible for the snow leopard and blue sheep distributions in the energy‐deficient environments of high altitudes. Currently, about 15.32% and 15.93% area of the Nepal Himalaya are suitable for snow leopard and blue sheep habitats, respectively. The bioclimatic models show that the current suitable habitats of both snow leopard and blue sheep will be reduced under future climate change. The predicted suitable habitat of the snow leopard is decreased when blue sheep habitats is incorporated in the model. Our climate‐only model shows that only 11.64% (17,190 km2) area of Nepal is suitable for the snow leopard under current climate and the suitable habitat reduces to 5,435 km2 (reduced by 24.02%) after incorporating the predicted distribution of blue sheep. The predicted distribution of snow leopard reduces by 14.57% in 2030 and by 21.57% in 2050 when the predicted distribution of blue sheep is included as compared to 1.98% reduction in 2030 and 3.80% reduction in 2050 based on the climate‐only model. It is predicted that future climate may alter the predator–prey spatial interaction inducing a lower degree of overlap and a higher degree of mismatch between snow leopard and blue sheep niches. This suggests increased energetic costs of finding preferred prey for snow leopards – a species already facing energetic constraints due to the limited dietary resources in its alpine habitat. Our findings provide valuable information for extension of protected areas in future. 相似文献
20.
Jan Plue Pieter De Frenne Kamal Acharya Jrg Brunet Olivier Chabrerie Guillaume Decocq Martin Diekmann Bente J. Graae Thilo Heinken Martin Hermy Annette Kolb Isgard Lemke Jaan Liira Tobias Naaf Anna Shevtsova Kris Verheyen Monika Wulf Sara A. O. Cousins 《Global Ecology and Biogeography》2013,22(10):1106-1117