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排序方式: 共有265条查询结果,搜索用时 15 毫秒
61.
Reverse breeding in Arabidopsis thaliana generates homozygous parental lines from a heterozygous plant 总被引:1,自引:0,他引:1
Wijnker E van Dun K de Snoo CB Lelivelt CL Keurentjes JJ Naharudin NS Ravi M Chan SW de Jong H Dirks R 《Nature genetics》2012,44(4):467-470
Traditionally, hybrid seeds are produced by crossing selected inbred lines. Here we provide a proof of concept for reverse breeding, a new approach that simplifies meiosis such that homozygous parental lines can be generated from a vigorous hybrid individual. We silenced DMC1, which encodes the meiotic recombination protein DISRUPTED MEIOTIC cDNA1, in hybrids of A. thaliana, so that non-recombined parental chromosomes segregate during meiosis. We then converted the resulting gametes into adult haploid plants, and subsequently into homozygous diploids, so that each contained half the genome of the original hybrid. From 36 homozygous lines, we selected 3 (out of 6) complementing parental pairs that allowed us to recreate the original hybrid by intercrossing. In addition, this approach resulted in a complete set of chromosome-substitution lines. Our method allows the selection of a single choice offspring from a segregating population and preservation of its heterozygous genotype by generating homozygous founder lines. 相似文献
62.
Entesarian M Matsson H Klar J Bergendal B Olson L Arakaki R Hayashi Y Ohuchi H Falahat B Bolstad AI Jonsson R Wahren-Herlenius M Dahl N 《Nature genetics》2005,37(2):125-127
Autosomal dominant aplasia of lacrimal and salivary glands (ALSG; OMIM 180920 and OMIM 103420) is a rare condition characterized by irritable eyes and dryness of the mouth. We mapped ALSG to 5p13.2-5q13.1, which coincides with the gene fibroblast growth factor 10 (FGF10). In two extended pedigrees, we identified heterozygous mutations in FGF10 in all individuals with ALSG. Fgf10(+/-) mice have a phenotype similar to ALSG, providing a model for this disorder. We suggest that haploinsufficiency for FGF10 during a crucial stage of development results in ALSG. 相似文献
63.
Manping Liu Zhenjie Wu Rui Yang Jiangtao Wei Yingda Yu P?l C. Skaret Hans J. Roven 《自然科学进展(英文版)》2015,25(2):153-158
In the present investigation, both static and dynamic precipitations of an Al–Mg–Si–Cu aluminum alloy after solid-solution treatment(SST)were comparatively analyzed using differential scanning calorimetry(DSC). Dynamic aging was performed in the SST alloy through equal channel angular pressing(ECAP) at different temperatures of room temperature, 110, 170, 191 and 300 1C. For comparison, static artificial aging was conducted in the SST alloy at 191 1C with two aging times of 4 and 10 h. The DSC analyses reveal that the dynamic precipitation has occurred in the ECAPed samples, while the activation energies associated with the strengthening precipitates in the dynamic samples are considerably higher than the energies in the SST and static aged samples. The higher activation energies are probably attributed to the smaller grains and higher dislocation density developed after ECAP. The results in the present investigation allow the prediction of the type of the dynamic precipitates to influence the strength of the ultrafine grained alloy during ECAP at various temperatures. 相似文献
64.
Daffonchio D Borin S Brusa T Brusetti L van der Wielen PW Bolhuis H Yakimov MM D'Auria G Giuliano L Marty D Tamburini C McGenity TJ Hallsworth JE Sass AM Timmis KN Tselepides A de Lange GJ Hübner A Thomson J Varnavas SP Gasparoni F Gerber HW Malinverno E Corselli C Garcin J McKew B Golyshin PN Lampadariou N Polymenakou P Calore D Cenedese S Zanon F Hoog S;Biodeep Scientific Party 《Nature》2006,440(7081):203-207
The chemical composition of the Bannock basin has been studied in some detail. We recently showed that unusual microbial populations, including a new division of Archaea (MSBL1), inhabit the NaCl-rich hypersaline brine. High salinities tend to reduce biodiversity, but when brines come into contact with fresher water the natural haloclines formed frequently contain gradients of other chemicals, including permutations of electron donors and acceptors, that may enhance microbial diversity, activity and biogeochemical cycling. Here we report a 2.5-m-thick chemocline with a steep NaCl gradient at 3.3 km within the water column betweeen Bannock anoxic hypersaline brine and overlying sea water. The chemocline supports some of the most biomass-rich and active microbial communities in the deep sea, dominated by Bacteria rather than Archaea, and including four major new divisions of Bacteria. Significantly higher metabolic activities were measured in the chemocline than in the overlying sea water and underlying brine; functional analyses indicate that a range of biological processes is likely to occur in the chemocline. Many prokaryotic taxa, including the phylogenetically new groups, were confined to defined salinities, and collectively formed a diverse, sharply stratified, deep-sea ecosystem with sufficient biomass to potentially contribute to organic geological deposits. 相似文献
65.
66.
MYCN haploinsufficiency is associated with reduced brain size and intestinal atresias in Feingold syndrome 总被引:3,自引:0,他引:3
van Bokhoven H Celli J van Reeuwijk J Rinne T Glaudemans B van Beusekom E Rieu P Newbury-Ecob RA Chiang C Brunner HG 《Nature genetics》2005,37(5):465-467
Feingold syndrome is characterized by variable combinations of esophageal and duodenal atresias, microcephaly, learning disability, syndactyly and cardiac defect. We show here that heterozygous mutations in the gene MYCN are present in Feingold syndrome. All mutations are predicted to disrupt both the full-length protein and a new shortened MYCN isoform, suggesting that multiple aspects of early embryogenesis and postnatal brain growth in humans are tightly regulated by MYCN dosage. 相似文献
67.
It is well known that some economic time series can be described by models which allow for either long memory or for occasional level shifts. In this paper we propose to examine the relative merits of these models by introducing a new model, which jointly captures the two features. We discuss representation and estimation. Using simulations, we demonstrate its forecasting ability, relative to the one‐feature models, both in terms of point forecasts and interval forecasts. We illustrate the model for daily S&P500 volatility. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
68.
Philip Hans Franses 《Journal of forecasting》1993,12(7):601-613
The univariate quarterly Dutch series of industrial production and money stock are both modelled with a periodically integrated subset autoregression (PISA). This model for a non-stationary series allows the lag orders, the values of the parameters and the cyclical patterns to vary over the seasons. The PISA models are found by applying a general-to-simple specification strategy, which deals with non-stationarity and periodicity simultaneously. It is found that the two series show a common asymmetric cyclical behaviour. This paper further proposes a test for periodicity in the errors, with which it is argued that a non-periodic model for the industrial production and money stock is misspecified and that seasonal adjustment does not remove periodicity in the autocorrelation function. 相似文献
69.
Eight glacial cycles from an Antarctic ice core 总被引:9,自引:0,他引:9
Augustin L Barbante C Barnes PR Barnola JM Bigler M Castellano E Cattani O Chappellaz J Dahl-Jensen D Delmonte B Dreyfus G Durand G Falourd S Fischer H Flückiger J Hansson ME Huybrechts P Jugie G Johnsen SJ Jouzel J Kaufmann P Kipfstuhl J Lambert F Lipenkov VY Littot GC Longinelli A Lorrain R Maggi V Masson-Delmotte V Miller H Mulvaney R Oerlemans J Oerter H Orombelli G Parrenin F Peel DA Petit JR Raynaud D Ritz C Ruth U Schwander J Siegenthaler U Souchez R Stauffer B Steffensen JP Stenni B 《Nature》2004,429(6992):623-628
The Antarctic Vostok ice core provided compelling evidence of the nature of climate, and of climate feedbacks, over the past 420,000 years. Marine records suggest that the amplitude of climate variability was smaller before that time, but such records are often poorly resolved. Moreover, it is not possible to infer the abundance of greenhouse gases in the atmosphere from marine records. Here we report the recovery of a deep ice core from Dome C, Antarctica, that provides a climate record for the past 740,000 years. For the four most recent glacial cycles, the data agree well with the record from Vostok. The earlier period, between 740,000 and 430,000 years ago, was characterized by less pronounced warmth in interglacial periods in Antarctica, but a higher proportion of each cycle was spent in the warm mode. The transition from glacial to interglacial conditions about 430,000 years ago (Termination V) resembles the transition into the present interglacial period in terms of the magnitude of change in temperatures and greenhouse gases, but there are significant differences in the patterns of change. The interglacial stage following Termination V was exceptionally long--28,000 years compared to, for example, the 12,000 years recorded so far in the present interglacial period. Given the similarities between this earlier warm period and today, our results may imply that without human intervention, a climate similar to the present one would extend well into the future. 相似文献
70.
Vik JO Stenseth NC Tavecchia G Mysterud A Lingjaerde OC 《Nature》2004,427(6976):697-8; discussion 698
Theory indicates that correlated weather may synchronize populations, but the extent to which this holds for non-identical, nonlinear systems is uncertain. Post and Forchhammer claim to have shown climate-induced synchrony for musk oxen and caribou that are separated by the Greenland ice sheet. However, logical and mathematical errors undermine their finding. Whether or not large-scale weather can be a major synchronizing factor across species remains an open question. 相似文献