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811.
Expression and inheritance of kanamycin resistance in a large number of transgenic petunias generated by Agrobacterium-mediated transformation 总被引:2,自引:0,他引:2
One hundred and four kanamycin-resistant Petunia Mitchell plants were regenerated from leaf discs cocultivated with Agrobacterium tumefaciens strain LBA4404 containing a binary vector pCGN200. Selection for kanamycin resistance was applied during plant regeneration at the initiation of both shoots and roots. The regenerated plants were analysed for expression and inheritance of their kanamycin resistance phenotype. Approximately half of the plants showed normal Mendelian inheritance for one or two kanamycin resistance genes. In one case, the two copies were inserted at closely linked sites on homologous chromosomes, and gave <0.05% kanamycin-sensitive progeny on backcrosses. Six plants had inheritance patterns suggesting that the kanamycin gene had inserted into an essential region of DNA. Forty-five plants showed lower than expected transmission of kanamycin resistance, which was associated with low expression of the resistance phenotype in most cases. Ten plants produced segregation ratios that are not readily interpreted by Mendelian inheritance. 相似文献
812.
D. R. Jensen 《Biometrical journal. Biometrische Zeitschrift》1988,30(5):533-544
This study develops simultaneous tests for shifts in marginal distributions pertaining to complete two-way multivariate data not having Gaussian errors. Gerig's (1969) statistics based on ranks are used, a special case yielding Friedman's (1937) χ Statistics statistics for the one-dimensional marginal distributions. Exact α-level procedures are not now available. Instead, approximate but conservative tests are constructed using available tables together with suitable probability inequalities. A variational result permits unlimited tests even when these are suggested by the data. The procedures are illustrated using data from field studies with peanuts; some extensions are noted; and selected percentage points are provided to support some of the tests. 相似文献
813.
The interspecific relationships of the following nine forms ofSaguinus were analyzed applying the multivariate analysis to the cranial measurements;S. oedipus, S. geoffroyi, S. leucopus, S. nigricollis, S. fuscicollis, S. labiatus, S. mystax, S. midas midas, andS. midas niger. Penrose's size distance was used to express the size factor among the nine forms; and for the shape factor, Q-mode correlation
coefficients were utilized. The shape distance betweenS. oedipus andS. geoffroyi was almost equal to that betweenS. nigricollis andS. fuscicollis which are recognized as different species based on biogeographical evidence. Furthermore, the Penrose's size distance betweenS. oedipus andS. geoffroyi was quite large. Therefore, the results of this study support the hypothesis thatS. oedipus andS. geoffroyi are valid species.
The analysis of the phylogenetic relationships among the nine forms was based on the shape factor only. The forms were divided
into two main clusters: (1)S. oedipus, S. geoffroyi, andS. leucopus; (2)S. nigricollis, S. fuscicollis, S. labiatus, S. mystax, S. midas midas, andS. midas niger. In the former cluster,S. oedipus was more closely related toS. geoffroyi than either was toS. leucopus. The latter cluster was subdivided in two subclusters based on the degree of their affinity: (2a)S. nigricollis, S. fuscicollis, S. labiatus, andS. mystax; and (2b)S. midas midas andS. midas niger. In the former subcluster, [S. nigricollis, S. fuscicollis] and [S. labiatus, S. mystax] were classified into clusters, respectively.
The ancestor of theS. nigricollis group differentiated intoS. oedipus, S. geoffroyi, andS. leucopus with the narrowing of the maxilla in the facial region, andS. midas midas andS. midas niger with the downward movement of rhinion. 相似文献
814.
Zhongwei Zhang Reinaldo B. Arellano-Valle Marc G. Genton Raphaël Huser 《Biometrics》2023,79(3):1788-1800
Correlated binary response data with covariates are ubiquitous in longitudinal or spatial studies. Among the existing statistical models, the most well-known one for this type of data is the multivariate probit model, which uses a Gaussian link to model dependence at the latent level. However, a symmetric link may not be appropriate if the data are highly imbalanced. Here, we propose a multivariate skew-elliptical link model for correlated binary responses, which includes the multivariate probit model as a special case. Furthermore, we perform Bayesian inference for this new model and prove that the regression coefficients have a closed-form unified skew-elliptical posterior with an elliptical prior. The new methodology is illustrated by an application to COVID-19 data from three different counties of the state of California, USA. By jointly modeling extreme spikes in weekly new cases, our results show that the spatial dependence cannot be neglected. Furthermore, the results also show that the skewed latent structure of our proposed model improves the flexibility of the multivariate probit model and provides a better fit to our highly imbalanced dataset. 相似文献
815.
When planning a two-arm group sequential clinical trial with a binary primary outcome that has severe implications for quality of life (e.g., mortality), investigators may strive to find the design that maximizes in-trial patient benefit. In such cases, Bayesian response-adaptive randomization (BRAR) is often considered because it can alter the allocation ratio throughout the trial in favor of the treatment that is currently performing better. Although previous studies have recommended using fixed randomization over BRAR based on patient benefit metrics calculated from the realized trial sample size, these previous comparisons have been limited by failures to hold type I and II error rates constant across designs or consider the impacts on all individuals directly affected by the design choice. In this paper, we propose a metric for comparing designs with the same type I and II error rates that reflects expected outcomes among individuals who would participate in the trial if enrollment is open when they become eligible. We demonstrate how to use the proposed metric to guide the choice of design in the context of two recent trials in persons suffering out of hospital cardiac arrest. Using computer simulation, we demonstrate that various implementations of group sequential BRAR offer modest improvements with respect to the proposed metric relative to conventional group sequential monitoring alone. 相似文献
816.
人类免疫球蛋白同种异型G2M(23)因子在中国人群中的分布 总被引:1,自引:0,他引:1
应用单克隆抗体酶联免疫吸附吸附抑制实验,对我国3个民族8个群体2104份血样进行了免疫球蛋白同种异型G2m(23)因子检测。经多元相关和多元回归分析发现,中国人G2m(23)基因频率分布呈沿海拔高度和纬度变化的渐变群,据此建立了可预测中国人群G2M(23)基因频率的多元回归方程,本文还讨论了G2m(23)基因频率形成渐变群的原因。 相似文献
817.
818.
The introduction of binary plasmids intoAgrobacterium hosts forAgrobacterium-mediated transformation of plants is most readily achieved by electroporation. However, occasionally, no transformed colonies
are recovered and the transformation program is delayed. Poor transformation rates are commonly associated with particular
combinations ofAgrobacterium strains and plasmid-selection markers. In order to avoid this problem, it is important for the bacteria to have a highly
competent status for reception of plasmid DNA. It is also important to optimize the level of antibiotic for the selection
of transformed colonies. In this article, we demonstrate that transformation competence is strongly related to the phase of
growth at which a bacterial culture is prepared for electroporation, and we describe a simple procedure that allows the level
of transformation-competent cells to be maximized. We have observed that there is significant variation between transformedAgrobacterium strains in the levels of antibiotic tolerance; we define the antibiotic levels that are appropriate for selection of threeArgobacterium tumefaciens (EHA101, LBA4404, C58) and twoArgobacterium rhizogenes (LBA9402, Ar2626) strains, transformed with three alternative resistance markers (spectinomycinres, kanamycinres, and gentamycinres). 相似文献
819.
Parameter expansion to accelerate EM: The PX-EM algorithm 总被引:7,自引:0,他引:7