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Natali Gulbahce

    Natali Gulbahce

    BGI, Research, Department Member
    Currently, the methods available for preimplantation genetic diagnosis (PGD) of in vitro fertilized (IVF) embryos do not detect de novo single-nucleotide and short indel mutations, which have been shown to cause a large fraction of... more
    Currently, the methods available for preimplantation genetic diagnosis (PGD) of in vitro fertilized (IVF) embryos do not detect de novo single-nucleotide and short indel mutations, which have been shown to cause a large fraction of genetic diseases. Detection of all these types of mutations requires whole-genome sequencing (WGS). In this study, advanced massively parallel WGS was performed on three 5- to 10-cell biopsies from two blastocyst-stage embryos. Both parents and paternal grandparents were also analyzed to allow for accurate measurements of false-positive and false-negative error rates. Overall, >95% of each genome was called. In the embryos, experimentally derived haplotypes and barcoded read data were used to detect and phase up to 82% of de novo single base mutations with a false-positive rate of about one error per Gb, resulting in fewer than 10 such errors per embryo. This represents a ∼100-fold lower error rate than previously published from 10 cells, and it is the...
    In the post-genomic era, organisms can be modelled at the whole-cell level in silico via steady state methods to describe their metabolic capabilities. We use two such methods, Flux Balance Analysis and Minimization of Metabolic... more
    In the post-genomic era, organisms can be modelled at the whole-cell level in silico via steady state methods to describe their metabolic capabilities. We use two such methods, Flux Balance Analysis and Minimization of Metabolic Adjustment to explore the behavior of cells (of E. coli and S. cerevisiae) after severe mutations. We propose experimentally feasible ways of modifying the underlying
    Despite the apparent conceptual boundaries of scientific fields, a formal description for their evolution is lacking. Here we describe a novel approach to study the dynamics and evolution of scientific fields using a network-based... more
    Despite the apparent conceptual boundaries of scientific fields, a formal description for their evolution is lacking. Here we describe a novel approach to study the dynamics and evolution of scientific fields using a network-based analysis. We build an idea network consisting of American Physical Society PACS numbers as nodes representing scientific concepts. Two PACS numbers are linked if there exist
    We present an efficient computational approach to sample the histories of nonlinear stochastic processes. This framework builds upon recent work on casting a d-dimensional stochastic dynamical system into a (d+1)-dimensional equilibrium... more
    We present an efficient computational approach to sample the histories of nonlinear stochastic processes. This framework builds upon recent work on casting a d-dimensional stochastic dynamical system into a (d+1)-dimensional equilibrium system using the path-integral approach. We introduce a cluster algorithm that efficiently samples histories and discuss how to include measurements that are available into the estimate of the histories. This allows our approach to be applicable to the simulation of rare events and to optimal state and parameter estimation. We demonstrate the utility of this approach for Phi4 Langevin dynamics in two spatial dimensions where our algorithm improves sampling efficiency up to an order of magnitude.
    Abstract It is generally expected that future and emerging nanoscale computing devices will be built in a bottom-up way from vast numbers of simple, densely arranged components that exhibit high failure rates, are relatively slow, and... more
    Abstract It is generally expected that future and emerging nanoscale computing devices will be built in a bottom-up way from vast numbers of simple, densely arranged components that exhibit high failure rates, are relatively slow, and connected in an unstructured way. Other than that, there is little to no consensus on what type of technology and computing architecture holds most promises to go far beyond today's top-down engineered silicon devices. Highly structured crossbar-like and cellular automata architectures have been ...
    Highly structured mesh-or crossbar-like nanoscale architectures have been proposed in the past as possible alternatives to the von Neumann computing architecture. While the top-down engineered semi-conducting technology favors regular and... more
    Highly structured mesh-or crossbar-like nanoscale architectures have been proposed in the past as possible alternatives to the von Neumann computing architecture. While the top-down engineered semi-conducting technology favors regular and locally interconnected ...
    Recent advances in genetics have spurred rapid progress towards the systematic identification of genes involved in complex diseases. Still, the detailed understanding of the molecular and physiological mechanisms through which these genes... more
    Recent advances in genetics have spurred rapid progress towards the systematic identification of genes involved in complex diseases. Still, the detailed understanding of the molecular and physiological mechanisms through which these genes impact disease phenotypes remains a major challenge. Here, we identify the asthma disease module, i.e. the local neighborhood of the interactome whose perturbation is associated with asthma, and validate it for functional and pathophysiological relevance, using both computational and experimental approaches. We find that the asthma disease module is enriched with modest GWAS p-values against the background of random variation, and with differentially expressed genes from normal and asthmatic fibroblast cells treated with an asthma specific drug. The asthma module also contains immune-response mechanisms that are shared with other immune-related disease modules. Further, using diverse omics (genomics, gene-expression, drug response) data, we identif...
    Genotypic differences greatly influence susceptibility and resistance to disease. Understanding genotype-phenotype relationships requires that phenotypes be viewed as manifestations of network properties, rather than simply as the result... more
    Genotypic differences greatly influence susceptibility and resistance to disease. Understanding genotype-phenotype relationships requires that phenotypes be viewed as manifestations of network properties, rather than simply as the result of individual genomic variations. Genome sequencing efforts have identified numerous germline mutations, and large numbers of somatic genomic alterations, associated with a predisposition to cancer. However, it remains difficult to distinguish background, or 'passenger', cancer mutations from causal, or…
    Pulmonary hypertension (PH) is driven by diverse pathogenic etiologies. Owing to their pleiotropic actions, microRNA molecules are potential candidates for coordinated regulation of these disease stimuli.
    A crossover from heterogeneous to homogeneous nucleation has been observed experimentally (e.g., in ADP) when the quench depth is increased. To understand this crossover behavior in detail, we have simulated heterogeneous and homogeneous... more
    A crossover from heterogeneous to homogeneous nucleation has been observed experimentally (e.g., in ADP) when the quench depth is increased. To understand this crossover behavior in detail, we have simulated heterogeneous and homogeneous nucleation in nearest-neighbor and long-range Ising models for various quench depths. We find that for a fixed system size the system crosses over from heterogeneous to homogeneous
    Abstract It is generally expected that future and emerging nanoscale computing devices will be built in a bottom-up way from vast numbers of simple, densely arranged components that exhibit high failure rates, are relatively slow, and... more
    Abstract It is generally expected that future and emerging nanoscale computing devices will be built in a bottom-up way from vast numbers of simple, densely arranged components that exhibit high failure rates, are relatively slow, and connected in an unstructured way. Other than that, there is little to no consensus on what type of technology and computing architecture holds most promises to go far beyond today's top-down engineered silicon devices. Highly structured crossbar-like and cellular automata architectures have been ...
    It has been shown [7, 6] that feedforward Boolean networks can learn to perform specific simple tasks and generalize well if only a subset of the learning examples is provided for learning. Here, we extend this body of work and show... more
    It has been shown [7, 6] that feedforward Boolean networks can learn to perform specific simple tasks and generalize well if only a subset of the learning examples is provided for learning. Here, we extend this body of work and show experimentally that random Boolean networks (RBNs), where both the interconnections and the Boolean transfer functions are chosen at random initially, can be evolved by using a state-topology evolution to solve simple tasks. We measure the learning and generalization performance, investigate the ...
    Many human diseases, arising from mutations of disease susceptibility genes (genetic diseases), are also associated with viral infections (virally implicated diseases), either in a directly causal manner or by indirect associations. Here... more
    Many human diseases, arising from mutations of disease susceptibility genes (genetic diseases), are also associated with viral infections (virally implicated diseases), either in a directly causal manner or by indirect associations. Here we examine whether viral perturbations of host interactome may underlie such virally implicated disease relationships. Using as models two different human viruses, Epstein-Barr virus (EBV) and human papillomavirus (HPV), we find that host targets of viral proteins reside in network proximity to products of disease susceptibility genes. Expression changes in virally implicated disease tissues and comorbidity patterns cluster significantly in the network vicinity of viral targets. The topological proximity found between cellular targets of viral proteins and disease genes was exploited to uncover a novel pathway linking HPV to Fanconi anemia.