Sequence organizations are viewed from two points: one is from informational redundancy or informational correlation (IC) and another is from k-mer frequency statistics. Two problems are investigated. The first is how the ICs exceed the fluctuation bound and the order emerges from fluctuation in a genome when the sequence length attains some critical value. We demonstrated that the transition from fluctuation to order takes place at about sequence length 200-300 thousands bases for human and E coli genome. It means that the life emerges from a region between macroscopic and microscopic. The second is about the statistical law of the k-mer organization in a genome under the evolutionary pressure and functional selection. We deduced a sum rule Q(k,N) on the k-mer frequency deviations from the randomness in a N-long sequence of genome and deduced the relations of Q(k,N) with k and N. We found that Q(k,N) increases with length N at a constant rate for most genome sequences and demonstrated that when the functional selection of k-mers is accumulated to some critical value the ordering takes place. An important finding is the sum rule correlated with the evolutionary complexity of the genome.
Uncovering Proximity of Chromosome Territories using Classical Algebraic Statistics
交换型染色体畸变(Exchange type chromosome aberrations,ETCA)是指染色体断裂后产生的片段与来自其他染色体的其他片段重新连接时发生的基因组重排。ETCA通常在癌细胞和暴露于辐射的细胞中观察到。这些染色体重排的频率与它们的空间接近性相关,因此它可以用来推断基因组的三维结构。由于数据的稀疏性,从癌症和辐射数据中提取空间邻近度的统计意义仍然有些难以捉摸。我们在这里提出了一种新的方法来研究的三维组织的基因组使用代数统计。我们测试我们的方法上公布的数据集的照射人血淋巴细胞。我们提供了一个严格的方法来测试基因组的整体组织,并在协议与以前的结果,我们发现一个随机的相对定位的染色体与染色体对\{1,22\}和\{13,14\},有一个显着更大的ETCA的数量比其余的染色体对,这表明他们的空间接近。我们的结论是,代数方法可以成功地用于分析遗传数据,并有潜在的应用到更大,更复杂的数据集。
Combining detection and reconstruction of correlational and quasi-periodic motifs in viral genomic sequences with transitional genome mapping: Application to COVID-19
基因组自身的过渡自同构映射(Transitional Automorphic Mapping of the Genome on Itself,TAMGI)方法旨在结合病毒基因组RNA/DNA序列中相关和准周期模体的检测和重建。通过TAMGI重建的基序对于插入缺失和点突变是稳健的,并且可以尝试作为推定的治疗靶标。我们开发并测试了相关的理论和统计标准的TAMGI应用程序。TAMGI的应用通过研究包装在类似病毒的螺旋衣壳中的严重急性呼吸道综合征冠状病毒SARS-CoV和SARS-CoV-2(后者的冠状病毒SARS-CoV-2负责COVID-19大流行)的基因组中的基序来说明。这样的核糖核衣壳被转运到球形膜被膜与掺入刺突糖蛋白。另外两个例子涉及二十面体衣壳病毒的基因组,卫星烟草花叶病毒(STMV)和噬菌体PHIX 174。这些病毒基因组中的部分准周期基序是由于基因组ssRNA/ssDNA与核衣壳蛋白之间的弱特异性合作相互作用而进化的。衣壳的对称性导致相关基因组序列中特定准周期基序的自然选择。一般来说,TAMGI为研究许多分子机制提供了一个方便的工具,这些机制涉及准周期基序和完整重复序列、基因组组织、顺式/反式调节元件的背景分析、数据挖掘以及基因组序列中的相关性。
Supregraph: Enabling Information-Optimal Assembly Graph Representation of a Read Set
Department of Computer Science and Engineering, Pennsylvania State University(宾夕法尼亚州立大学计算机科学与工程系);Huck Institutes of the Life Sciences, Pennsylvania State University(宾夕法尼亚州立大学哈克生命科学学院)