scholarly journals Phenotypic and Genomic Local Adaptation across Latitude and Altitude in Populus trichocarpa

2019 ◽  
Vol 11 (8) ◽  
pp. 2256-2272 ◽  
Author(s):  
Man Zhang ◽  
Haktan Suren ◽  
Jason A Holliday

Abstract Local adaptation to climate allows plants to cope with temporally and spatially heterogeneous environments, and parallel phenotypic clines provide a natural experiment to uncover the genomic architecture of adaptation. Though extensive effort has been made to investigate the genomic basis of local adaptation to climate across the latitudinal range of tree species, less is known for altitudinal clines. We used exome capture to genotype 451 Populus trichocarpa genotypes across altitudinal and latitudinal gradients spanning the natural species range, and phenotyped these trees for a variety of adaptive traits in two common gardens. We observed clinal variation in phenotypic traits across the two transects, which indicates climate-driven selection, and coupled gene-based genotype–phenotype and genotype–environment association scans to identify imprints of climatic adaptation on the genome. Although many of the phenotype- and climate-associated genes were unique to one transect, we found evidence of parallelism between latitude and altitude, as well as significant convergence when we compared our outlier genes with those putatively involved in climatic adaptation in two gymnosperm species. These results suggest that not only genomic constraint during adaptation to similar environmental gradients in poplar but also different environmental contexts, spatial scale, and perhaps redundant function among potentially adaptive genes and polymorphisms lead to divergent adaptive architectures.


2018 ◽  
Vol 285 (1881) ◽  
pp. 20180519 ◽  
Author(s):  
Claire Mérot ◽  
Emma L. Berdan ◽  
Charles Babin ◽  
Eric Normandeau ◽  
Maren Wellenreuther ◽  
...  

Large chromosomal rearrangements are thought to facilitate adaptation to heterogeneous environments by limiting genomic recombination. Indeed, inversions have been implicated in adaptation along environmental clines and in ecotype specialization. Here, we combine classical ecological studies and population genetics to investigate an inversion polymorphism previously documented in Europe among natural populations of the seaweed fly Coelopa frigida along a latitudinal cline in North America. We test if the inversion is present in North America and polymorphic, assess which environmental conditions modulate the inversion karyotype frequencies, and document the relationship between inversion karyotype and adult size. We sampled nearly 2000 flies from 20 populations along several environmental gradients to quantify associations of inversion frequencies to heterogeneous environmental variables. Genotyping and phenotyping showed a widespread and conserved inversion polymorphism between Europe and America. Variation in inversion frequency was significantly associated with environmental factors, with parallel patterns between continents, indicating that the inversion may play a role in local adaptation. The three karyotypes of the inversion are differently favoured across micro-habitats and represent life-history strategies likely to be maintained by the collective action of several mechanisms of balancing selection. Our study adds to the mounting evidence that inversions are facilitators of adaptation and enhance within-species diversity.



2018 ◽  
Author(s):  
Claire Mérot ◽  
Emma Berdan ◽  
Charles Babin ◽  
Eric Normandeau ◽  
Maren Wellenreuther ◽  
...  

AbstractLarge chromosomal rearrangements are thought to facilitate adaptation to heterogeneous environments by limiting genomic recombination. Indeed, inversions have been implicated in adaptation along environmental clines and in ecotype specialisation. Here, we combine classical ecological studies and population genetics to investigate an inversion polymorphism previously documented in Europe among natural populations of the seaweed fly Coelopa frigida along a latitudinal cline in North America. We test if the inversion is present in North America and polymorphic, assess which environmental conditions modulate the inversion karyotype frequencies, and document the relationship between inversion karyotype and adult size. We sampled nearly 2,000 flies from 20 populations along several environmental gradients to quantify associations of inversion frequencies to heterogeneous environmental variables. Genotyping and phenotyping showed a widespread and conserved inversion polymorphism between Europe and America. Variation in inversion frequency was significantly associated with environmental factors, with parallel patterns between continents, indicating that the inversion may play a role in local adaptation. The three karyotypes of the inversion are differently favoured across micro-habitats and represent life-history strategies likely maintained by the collective action of several mechanisms of balancing selection. Our study adds to the mounting evidence that inversions are facilitators of adaptation and enhance within-species diversity.



2019 ◽  
Vol 15 (6) ◽  
Author(s):  
Lili Li ◽  
Jun Chen ◽  
Martin Lascoux

AbstractForest trees exhibit strong patterns of local adaptation in phenological traits along latitudinal gradients. Previous studies in spruce have shown that variation at genes from the photoperiodic pathway and the circadian clock are associated to these clines but it has been difficult to find solid evidence of selection for some of these genes. Here, we used growth cessation, gene expression, and single nucleotide polymorphism (SNP) data at two major candidate loci, FLOWERING LOCUS T/TERMINAL FLOWER1-Like2 (FTL2) and GIGANTEA (GI), as well as at background loci from a latitudinal gradient in Siberian spruce (Picea obovata) populations along the Ob River to test for clinal variation in growth cessation and at the two candidate genes. As in previous studies, there was a strong latitudinal cline in growth cessation that was accompanied by a significant cline in the expression of FTL2. Expression of FTL2 was significantly associated with allele frequencies at some of the GI’s SNPs. However, the cline in allele frequency at candidate genes was not as steep as in a Norway spruce cline and in a parallel Siberian spruce cline studied previously and nonsignificant when a correction for population structure was applied. A McDonald-Kreitman test did not detect decisive evidence of selection on GI (p value = 0.07) and could not be applied to FTL2 because of limited polymorphism. Nonetheless, polymorphisms contributed more to the increased neutrality index of PoGI than to that of control loci. Finally, comparing the results of two previously published studies to our new dataset led to the identification of strong candidate SNPs for local adaptation in FTL2 promoter and GI.



2014 ◽  
Author(s):  
Alan O. Bergland ◽  
Ray Tobler ◽  
Josefa Gonzalez ◽  
Paul Schmidt ◽  
Dmitri Petrov

Populations arrayed along broad latitudinal gradients often show patterns of clinal variation in phenotype and genotype. Such population differentiation can be generated and maintained by historical demographic events and local adaptation. These evolutionary forces are not mutually exclusive and, moreover, can in some cases produce nearly identical patterns of genetic differentiation among populations. Here, we investigate the evolutionary forces that generated and maintain clinal variation genome-wide among populations ofDrosophila melanogastersampled in North America and Australia. We contrast patterns of clinal variation in these continents with patterns of differentiation among ancestral European and African populations. Using established and novel methods we derive here, we show that recently derived North America and Australia populations were likely founded by both European and African lineages and that this admixture event contributed to genome-wide patterns of parallel clinal variation. The pervasive effects of admixture meant that only a handful of loci could be attributed to the operation of spatially varying selection using an FST outlier approach. Our results provide novel insight into the well-studied system of clinal differentiation inD. melanogasterand provide a context for future studies seeking to identify loci contributing to local adaptation in a wide variety of organisms, including other invasive species as well as some temperate endemics.



2021 ◽  
Author(s):  
Yi Hu ◽  
Robert D Guy ◽  
Raju Y Soolanayakanahally

Abstract Plants acquire multiple resources from the environment and may need to adjust and/or balance their respective resource-use efficiencies to maximize grow and survival, in a locally adaptive manner. In this study, tissue and whole-plant carbon isotopic composition (δ13C) and C/N ratios provided long-term measures of use efficiencies for water (WUE) and nitrogen (NUE), and a nitrogen isotopic composition (δ15N) based mass balance model was used to estimate traits related to N uptake and assimilation in heart-leaved willow (Salix eriocephala Michx.). In an initial common garden experiment consisting of 34 populations, we found population level variation in δ13C, C/N and δ15N, indicating different patterns in WUE, NUE and N uptake and assimilation. Although there was no relationship between foliar δ13C and C/N ratios among populations, there was a significant negative correlation between these measures across all individuals, implying a genetic and/or plastic trade-off between WUE and NUE not associated with local adaptation. To eliminate any environmental effect, we grew a subset of 21 genotypes hydroponically with nitrate as the sole N-source, and detected significant variation in δ13C, δ15N and C/N ratios. Variation in δ15N was mainly due to genotypic differences in the nitrate efflux/influx ratio (E/I) at the root. Both experiments suggested clinal variation in δ15N (and thus N uptake efficiency) with latitude of origin, which may relate to water availability and could contribute to global patterns in ecosystem δ15N. There was a tendency for genotypes with higher WUE to come from more water replete sites with shorter and cooler growing seasons. We found that δ13C, C/N, and E/I were not inter-correlated, suggesting that selection of growth, WUE, NUE and N uptake efficiency can occur without trade-off.





2020 ◽  
Author(s):  
Katherine M. Eaton ◽  
Moisés A. Bernal ◽  
Nathan J.C. Backenstose ◽  
Trevor J. Krabbenhoft

AbstractLocal adaptation can drive diversification of closely related species across environmental gradients and promote convergence of distantly related taxa that experience similar conditions. We examined a potential case of adaptation to novel visual environments in a species flock (Great Lakes salmonids, genus Coregonus) using a new amplicon genotyping protocol on the Oxford Nanopore Flongle. Five visual opsin genes were amplified for individuals of C. artedi, C. hoyi, C. kiyi, and C. zenithicus. Comparisons revealed species-specific differences in the coding sequence of rhodopsin (Tyr261Phe substitution), suggesting local adaptation by C. kiyi to the blue-shifted depths of Lake Superior. Parallel evolution and “toggling” at this amino acid residue has occurred several times across the fish tree of life, resulting in identical changes to the visual systems of distantly related taxa across replicated environmental gradients. Our results suggest that ecological differences and local adaptation to distinct visual environments are strong drivers of both evolutionary parallelism and diversification.



2021 ◽  
Vol 8 ◽  
Author(s):  
Peter von Dassow ◽  
Paula Valentina Muñoz Farías ◽  
Sarah Pinon ◽  
Esther Velasco-Senovilla ◽  
Simon Anguita-Salinas

The cosmopolitan phytoplankter Emiliania huxleyi contrasts with its closest relatives that are restricted to narrower latitudinal bands, making it interesting for exploring how alternative outcomes in phytoplankton range distributions arise. Mitochondrial and chloroplast haplogroups within E. huxleyi are shared with their closest relatives: Some E. huxleyi share organelle haplogroups with Gephyrocapsa parvula and G. ericsonii which inhabit lower latitudes, while other E. huxleyi share organelle haplogroups with G. muellerae, which inhabit high latitudes. We investigated whether the phylogeny of E. huxleyi organelles reflects environmental gradients, focusing on the Southeast Pacific where the different haplogroups and species co-occur. There was a high congruence between mitochondrial and chloroplast haplogroups within E. huxleyi. Haplogroup II of E. huxleyi is negatively associated with cooler less saline waters, compared to haplogroup I, both when analyzed globally and across temporal variability at the small special scale of a center of coastal upwelling at 30° S. A new mitochondrial haplogroup Ib detected in coastal Chile was associated with warmer waters. In an experiment focused on inter-species comparisons, laboratory-determined thermal reaction norms were consistent with latitudinal/thermal distributions of species, with G. oceanica exhibiting warm thermal optima and tolerance and G. muellerae exhibiting cooler thermal optima and tolerances. Emiliania huxleyi haplogroups I and II tended to exhibit a wider thermal niche compared to the other Gephyrocapsa, but no differences among haplogroups within E. huxleyi were found. A second experiment, controlling for local adaptation and time in culture, found a significant difference between E. huxleyi haplogroups. The difference between I and II was of the expected sign, but not the difference between I and Ib. The differences were small (≤1°C) compared to differences reported previously within E. huxleyi by local adaptation and even in-culture evolution. Haplogroup Ib showed a narrower thermal niche. The cosmopolitanism of E. huxleyi might result from both wide-spread generalist phenotypes and specialist phenotypes, as well as a capacity for local adaptation. Thermal reaction norm differences can well explain the species distributions but poorly explain distributions among mitochondrial haplogroups within E. huxleyi. Perhaps organelle haplogroup distributions reflect historical rather than selective processes.



2020 ◽  
Vol 117 (30) ◽  
pp. 17482-17490 ◽  
Author(s):  
Mark C. Urban ◽  
Sharon Y. Strauss ◽  
Fanie Pelletier ◽  
Eric P. Palkovacs ◽  
Mathew A. Leibold ◽  
...  

Historically, many biologists assumed that evolution and ecology acted independently because evolution occurred over distances too great to influence most ecological patterns. Today, evidence indicates that evolution can operate over a range of spatial scales, including fine spatial scales. Thus, evolutionary divergence across space might frequently interact with the mechanisms that also determine spatial ecological patterns. Here, we synthesize insights from 500 eco-evolutionary studies and develop a predictive framework that seeks to understand whether and when evolution amplifies, dampens, or creates ecological patterns. We demonstrate that local adaptation can alter everything from spatial variation in population abundances to ecosystem properties. We uncover 14 mechanisms that can mediate the outcome of evolution on spatial ecological patterns. Sometimes, evolution amplifies environmental variation, especially when selection enhances resource uptake or patch selection. The local evolution of foundation or keystone species can create ecological patterns where none existed originally. However, most often, we find that evolution dampens existing environmental gradients, because local adaptation evens out fitness across environments and thus counteracts the variation in associated ecological patterns. Consequently, evolution generally smooths out the underlying heterogeneity in nature, making the world appear less ragged than it would be in the absence of evolution. We end by highlighting the future research needed to inform a fully integrated and predictive biology that accounts for eco-evolutionary interactions in both space and time.



BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Fernando P. Guerra ◽  
Haktan Suren ◽  
Jason Holliday ◽  
James H. Richards ◽  
Oliver Fiehn ◽  
...  

Abstract Background Populus trichocarpa is an important forest tree species for the generation of lignocellulosic ethanol. Understanding the genomic basis of biomass production and chemical composition of wood is fundamental in supporting genetic improvement programs. Considerable variation has been observed in this species for complex traits related to growth, phenology, ecophysiology and wood chemistry. Those traits are influenced by both polygenic control and environmental effects, and their genome architecture and regulation are only partially understood. Genome wide association studies (GWAS) represent an approach to advance that aim using thousands of single nucleotide polymorphisms (SNPs). Genotyping using exome capture methodologies represent an efficient approach to identify specific functional regions of genomes underlying phenotypic variation. Results We identified 813 K SNPs, which were utilized for genotyping 461 P. trichocarpa clones, representing 101 provenances collected from Oregon and Washington, and established in California. A GWAS performed on 20 traits, considering single SNP-marker tests identified a variable number of significant SNPs (p-value < 6.1479E-8) in association with diameter, height, leaf carbon and nitrogen contents, and δ15N. The number of significant SNPs ranged from 2 to 220 per trait. Additionally, multiple-marker analyses by sliding-windows tests detected between 6 and 192 significant windows for the analyzed traits. The significant SNPs resided within genes that encode proteins belonging to different functional classes as such protein synthesis, energy/metabolism and DNA/RNA metabolism, among others. Conclusions SNP-markers within genes associated with traits of importance for biomass production were detected. They contribute to characterize the genomic architecture of P. trichocarpa biomass required to support the development and application of marker breeding technologies.



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