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151.
Juan Jia Zhenjiao Cao Chengzhu Liu Zhenhua Zhang Li Lin Yiyun Wang Negar Haghipour Lukas Wacker Hongyan Bao Thorston Dittmar Myrna J. Simpson Huan Yang Thomas W. Crowther Timothy I. Eglinton Jin‐Sheng He Xiaojuan Feng 《Global Change Biology》2019,25(12):4383-4393
Subsoil contains more than half of soil organic carbon (SOC) globally and is conventionally assumed to be relatively unresponsive to warming compared to the topsoil. Here, we show substantial changes in carbon allocation and dynamics of the subsoil but not topsoil in the Qinghai‐Tibetan alpine grasslands over 5 years of warming. Specifically, warming enhanced the accumulation of newly synthesized (14C‐enriched) carbon in the subsoil slow‐cycling pool (silt‐clay fraction) but promoted the decomposition of plant‐derived lignin in the fast‐cycling pool (macroaggregates). These changes mirrored an accumulation of lipids and sugars at the expense of lignin in the warmed bulk subsoil, likely associated with shortened soil freezing period and a deepening root system. As warming is accompanied by deepening roots in a wide range of ecosystems, root‐driven accrual of slow‐cycling pool may represent an important and overlooked mechanism for a potential long‐term carbon sink at depth. Moreover, given the contrasting sensitivity of SOC dynamics at varied depths, warming studies focusing only on surface soils may vastly misrepresent shifts in ecosystem carbon storage under climate change. 相似文献
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153.
Natural populations often exist in spatially diverse environments and may experience variation in the strength and targets of natural selection across their ranges. Drosophila provides an excellent opportunity to study the effects of spatially varying selection in natural populations, as both Drosophila melanogaster and Drosophila simulans live across a wide range of environments in North America. Here, we characterize patterns of variation in transposable elements (TEs) from six populations of D. melanogaster and nine populations of D. simulans sampled from multiple latitudes across North America. We find a nearly twofold excess of TEs in D. melanogaster relative to D. simulans, with this difference largely driven by TEs segregating at the lowest and highest allele frequencies. We find no effect of latitude on either total TE abundance or average TE allele frequencies in either species. Moreover, we show that, as a class of mutations, the most common patterns of TE variation do not coincide with the sampled latitudinal gradient, nor are they consistent with local adaptation acting on environmental differences found in the most extreme latitudes. We also do not find a cline in ancestry for North American D. melanogaster—for either TEs or single nucleotide polymorphisms—suggesting a limited role for demography in shaping patterns of TE variation. Though we find little evidence for widespread clinality among TEs in Drosophila, this does not necessarily imply a limited role for TEs in adaptation. We discuss the need for improved models of adaptation to large‐scale environmental heterogeneity, and how these might be applied to TEs. 相似文献
154.
Christine A. Bricault Karina Yusim Michael S. Seaman Hyejin Yoon James Theiler Elena E. Giorgi Kshitij Wagh Maxwell Theiler Peter Hraber Jennifer P. Macke Edward F. Kreider Gerald H. Learn Beatrice H. Hahn Johannes F. Scheid James M. Kovacs Jennifer L. Shields Christy L. Lavine Fadi Ghantous Bette Korber 《Cell host & microbe》2019,25(1):59-72.e8
155.
Meredith M. Doellman Scott P. Egan Gregory J. Ragland Peter J. Meyers Glen R. Hood Thomas H. Q. Powell Peter Lazorchak Daniel A. Hahn Stewart H. Berlocher Patrik Nosil Jeffrey L. Feder 《Ecology and evolution》2019,9(1):393-409
Taxa harboring high levels of standing variation may be more likely to adapt to rapid environmental shifts and experience ecological speciation. Here, we characterize geographic and host‐related differentiation for 10,241 single nucleotide polymorphisms in Rhagoletis pomonella fruit flies to infer whether standing genetic variation in adult eclosion time in the ancestral hawthorn (Crataegus spp.)‐infesting host race, as opposed to new mutations, contributed substantially to its recent shift to earlier fruiting apple (Malus domestica). Allele frequency differences associated with early vs. late eclosion time within each host race were significantly related to geographic genetic variation and host race differentiation across four sites, arrayed from north to south along a 430‐km transect, where the host races co‐occur in sympatry in the Midwest United States. Host fruiting phenology is clinal, with both apple and hawthorn trees fruiting earlier in the North and later in the South. Thus, we expected alleles associated with earlier eclosion to be at higher frequencies in northern populations. This pattern was observed in the hawthorn race across all four populations; however, allele frequency patterns in the apple race were more complex. Despite the generally earlier eclosion timing of apple flies and corresponding apple fruiting phenology, alleles on chromosomes 2 and 3 associated with earlier emergence were paradoxically at lower frequency in the apple than hawthorn host race across all four sympatric sites. However, loci on chromosome 1 did show higher frequencies of early eclosion‐associated alleles in the apple than hawthorn host race at the two southern sites, potentially accounting for their earlier eclosion phenotype. Thus, although extensive clinal genetic variation in the ancestral hawthorn race exists and contributed to the host shift to apple, further study is needed to resolve details of how this standing variation was selected to generate earlier eclosing apple fly populations in the North. 相似文献
156.
157.
Rajesh Kumar Tewari Soo Yeon Lee Eun Joo Hahn Kee Yoeup Paek 《Plant biotechnology reports》2007,1(4):227-235
Nitric oxide (NO) is a diffusible, gaseous signaling molecule. In plants, NO influences growth and development, and it can
also affect plant responses to various stresses. Because NO induces root differentiation and interacts with reactive oxygen
species, we examined the temporal effect of NO elicitation on root growth, saponin accumulation and antioxidant defense responses
in the adventitious roots of mountain ginseng (Panax ginseng). The observations revealed that NO is involved in root growth and saponin production. Elicitation with sodium nitroprusside
(SNP) activated O2
−-generating NADPH oxidase (NOX) activity, which most probably subsequently enhanced growth of adventitious roots of mountain
ginseng. A severe inhibition of NOX activity and decline in dry weight of SNP elicited adventitious roots in the presence
of NOX inhibitor (diphenyl iodonium, DPI), which further supports involvement of NOX in root growth. Enhanced activities of
antioxidant enzymes by SNP appear to be responsible for low H2O2, less lipid peroxidation, and modulation of ascorbate and non-protein thiol statuses in the adventitious roots of mountain
ginseng. Dry mass, saponin content and NOX activity was related with NO content present in adventitious roots of mountain
ginseng. 相似文献
158.
159.
Burnett KG Bain LJ Baldwin WS Callard GV Cohen S Di Giulio RT Evans DH Gómez-Chiarri M Hahn ME Hoover CA Karchner SI Katoh F Maclatchy DL Marshall WS Meyer JN Nacci DE Oleksiak MF Rees BB Singer TD Stegeman JJ Towle DW Van Veld PA Vogelbein WK Whitehead A Winn RN Crawford DL 《Comparative biochemistry and physiology. Part D, Genomics & proteomics》2007,2(4):257-286
A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their environment. In this paper we summarize an extensive body of work examining the adaptive responses of Fundulus species to environmental conditions, and describe how this research has contributed importantly to our understanding of physiology, gene regulation, toxicology, and ecological and evolutionary genetics of teleosts and other vertebrates. These explorations have reached a critical juncture at which advancement is hindered by the lack of genomic resources for these species. We suggest that a more complete genomics toolbox for F. heteroclitus and related species will permit researchers to exploit the power of this model organism to rapidly advance our understanding of fundamental biological and pathological mechanisms among vertebrates, as well as ecological strategies and evolutionary processes common to all living organisms. 相似文献
160.
Roth C Rastogi S Arvestad L Dittmar K Light S Ekman D Liberles DA 《Journal of experimental zoology. Part B. Molecular and developmental evolution》2007,308(1):58-73
Gene duplication is postulated to have played a major role in the evolution of biological novelty. Here, gene duplication is examined across levels of biological organization in an attempt to create a unified picture of the mechanistic process by which gene duplication can have played a role in generating biodiversity. Neofunctionalization and subfunctionalization have been proposed as important processes driving the retention of duplicate genes. These models have foundations in population genetic theory, which is now being refined by explicit consideration of the structural constraints placed upon genes encoding proteins through physical chemistry. Further, such models can be examined in the context of comparative genomics, where an integration of gene-level evolution and species-level evolution allows an assessment of the frequency of duplication and the fate of duplicate genes. This process, of course, is dependent upon the biochemical role that duplicated genes play in biological systems, which is in turn dependent upon the mechanism of duplication: whole genome duplication involving a co-duplication of interacting partners vs. single gene duplication. Lastly, the role that these processes may have played in driving speciation is examined. 相似文献