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101.
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Emma E. M. Knowles Samuel R. Mathias Josephine Mollon Amanda Rodrigue Marinka M. G. Koenis Thomas D. Dyer Harald H. H. Goring Joanne E. Curran Rene L. Olvera Ravi Duggirala Laura Almasy John Blangero David C. Glahn 《Genes, Brain & Behavior》2019,18(4)
Processing speed is a psychological construct that refers to the speed with which an individual can perform any cognitive operation. Processing speed correlates strongly with general cognitive ability, declines sharply with age and is impaired across a number of neurological and psychiatric disorders. Thus, identifying genes that influence processing speed will likely improve understanding of the genetics of intelligence, biological aging and the etiologies of numerous disorders. Previous genetics studies of processing speed have relied on simple phenotypes (eg, mean reaction time) derived from single tasks. This strategy assumes, erroneously, that processing speed is a unitary construct. In the present study, we aimed to characterize the genetic architecture of processing speed by using a multidimensional model applied to a battery of cognitive tasks. Linkage and QTL‐specific association analyses were performed on the factors from this model. The randomly ascertained sample comprised 1291 Mexican‐American individuals from extended pedigrees. We found that performance on all three distinct processing‐speed factors (Psychomotor Speed; Sequencing and Shifting and Verbal Fluency) were moderately and significantly heritable. We identified a genome‐wide significant quantitative trait locus (QTL) on chromosome 3q23 for Psychomotor Speed (LOD = 4.83). Within this locus, we identified a plausible and interesting candidate gene for Psychomotor Speed (Z = 2.90, P = 1.86 × 10?03). 相似文献
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Mariano Avino Garway T. Ng Yiying He Mathias S. Renaud Bradley R. Jones Art F. Y. Poon 《Ecology and evolution》2019,9(12):6756-6771
Cophylogeny is the congruence of phylogenetic relationships between two different groups of organisms due to their long‐term interaction. We investigated the use of tree shape distance measures to quantify the degree of cophylogeny. We implemented a reverse‐time simulation model of pathogen phylogenies within a fixed host tree, given cospeciation probability, host switching, and pathogen speciation rates. We used this model to evaluate 18 distance measures between host and pathogen trees including two kernel distances that we developed for labeled and unlabeled trees, which use branch lengths and accommodate different size trees. Finally, we used these measures to revisit published cophylogenetic studies, where authors described the observed associations as representing a high or low degree of cophylogeny. Our simulations demonstrated that some measures are more informative than others with respect to specific coevolution parameters especially when these did not assume extreme values. For real datasets, trees’ associations projection revealed clustering of high concordance studies suggesting that investigators are describing it in a consistent way. Our results support the hypothesis that measures can be useful for quantifying cophylogeny. This motivates their usage in the field of coevolution and supports the development of simulation‐based methods, i.e., approximate Bayesian computation, to estimate the underlying coevolutionary parameters. 相似文献
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In vivo and in vitro requirements for the formation of cytochrome b(6) were examined to analyze the mechanisms of transmembrane b-type cytochrome formation. After heterologous expression of spinach cytochrome b(6), formation of the holo-cytochrome was observed within the E. coli inner membrane. The transmembrane orientation of cytochrome b(6) appeared not to be critical for heme binding and holo-cytochrome formation. Furthermore, in vitro reconstitution of cytochrome b(6) was possible under oxidizing as well as under reducing conditions. Taken together these observations strongly indicate that transmembrane b-type cytochromes can spontaneously assemble in vitro as well as in a membrane. 相似文献
108.
Daus ML Grote M Müller P Doebber M Herrmann A Steinhoff HJ Dassa E Schneider E 《The Journal of biological chemistry》2007,282(31):22387-22396
We have investigated conformational changes of the purified maltose ATP-binding cassette transporter (MalFGK(2)) upon binding of ATP. The transport complex is composed of a heterodimer of the hydrophobic subunits MalF and MalG constituting the translocation pore and of a homodimer of MalK, representing the ATP-hydrolyzing subunit. Substrate is delivered to the transporter in complex with periplasmic maltose-binding protein (MalE). Cross-linking experiments with a variant containing an A85C mutation within the Q-loop of each MalK monomer indicated an ATP-induced shortening of the distance between both monomers. Cross-linking caused a substantial inhibition of MalE-maltose-stimulated ATPase activity. We further demonstrated that a mutation affecting the "catalytic carboxylate" (E159Q) locks the MalK dimer in the closed state, whereas a transporter containing the "ABC signature" mutation Q140K permanently resides in the resting state. Cross-linking experiments with variants containing the A85C mutation combined with cysteine substitutions in the conserved EAA motifs of MalF and MalG, respectively, revealed close proximity of these residues in the resting state. The formation of a MalK-MalG heterodimer remained unchanged upon the addition of ATP, indicating that MalG-EAA moves along with MalK during dimer closure. In contrast, the yield of MalK-MalF dimers was substantially reduced. This might be taken as further evidence for asymmetric functions of both EAA motifs. Cross-linking also caused inhibition of ATPase activity, suggesting that transporter function requires conformational changes of both EAA motifs. Together, our data support ATP-driven MalK dimer closure and reopening as crucial steps in the translocation cycle of the intact maltose transporter and are discussed with respect to a current model. 相似文献
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Dobbertin M Wermelinger B Bigler C Bürgi M Carron M Forster B Gimmi U Rigling A 《TheScientificWorldJournal》2007,7(Z1):231-239
In the dry Swiss Rhone Valley, Scots pine forests have experienced increased mortality in recent years. It has commonly been assumed that drought events and bark beetles fostered the decline, however, whether bark beetle outbreaks increased in recent years and whether they can be linked to drought stress or increasing temperature has never been studied. In our study, we correlated time series of drought indices from long-term climate stations, 11-year mortality trends from a long-term research plot, and mortality probabilities modeled from tree rings (as an indicator of tree vitality) with documented occurrences of various bark beetle species and a buprestid beetle, using regional Forest Service reports from 1902 to 2003 and advisory cases of the Swiss Forest Protection Service (SFPS) from 1984 to 2005. We compared the historical findings with measured beetle emergence from a 4-year tree felling and breeding chamber experiment. The documented beetle-related pine mortality cases increased dramatically in the 1990s, both in the forest reports and the advisory cases. The incidents of beetle-related pine mortality correlated positively with spring and summer temperature, and with the tree-ring based mortality index, but not with the drought index. The number of advisory cases, on the other hand, correlated slightly with summer drought index and temperature, but very highly with tree-ring-based mortality index. The tree-ring-based mortality index and observed tree mortality increased in years following drought. This was confirmed by the beetle emergences from felled trees. Following dry summers, more than twice as many trees were colonized by beetles than following wet summers. We conclude that increased temperatures in the Swiss Rhone Valley have likely weakened Scots pines and favored phloeophagous beetle population growth. Beetles contributed to the increased pine mortality following summer drought. Among the factors not addressed in this study, changed forest use may have also contributed to increased beetle populations and Scots pine mortality, whereas air pollution seems to be of lesser importance. 相似文献
110.
Nathan W. Bailey Mathias Klliker 《Evolution; international journal of organic evolution》2019,73(8):1549-1563
Our understanding of the evolutionary stability of socially selected traits is dominated by sexual selection models originating with R. A. Fisher, in which genetic covariance arising through assortative mating can trigger exponential, runaway trait evolution. To examine whether nonreproductive, socially selected traits experience similar dynamics—social runaway—when assortative mating does not automatically generate a covariance, we modeled the evolution of socially selected badge and donation phenotypes incorporating indirect genetic effects (IGEs) arising from the social environment. We establish a social runaway criterion based on the interaction coefficient, ψ , which describes social effects on badge and donation traits. Our models make several predictions. (1) IGEs can drive the original evolution of altruistic interactions that depend on receiver badges. (2) Donation traits are more likely to be susceptible to IGEs than badge traits. (3) Runaway dynamics in nonsexual, social contexts can occur in the absence of a genetic covariance. (4) Traits elaborated by social runaway are more likely to involve reciprocal, but nonsymmetrical, social plasticity. Models incorporating plasticity to the social environment via IGEs illustrate conditions favoring social runaway, describe a mechanism underlying the origins of costly traits, such as altruism, and support a fundamental role for phenotypic plasticity in rapid social evolution. 相似文献