Mandecki W, Krajewska-Grynkiewicz K, Klopotowski T
Genetics. 1986 Oct;114(2):633-57. doi: 10.1093/genetics/114.2.633.
A mathematical model for nonrandom generalized transduction is proposed and analyzed. The model takes into account the finite number of transducing particle classes for any given marker. The equations for estimation of the distance between markers from contransduction frequency data are derived and standard errors of the estimates are given. The obtained relationships depend significantly on the number of classes of transducing fragments. The model was applied to estimate the number of transducing fragment classes for a given marker in transduction with phage P22 of Salmonella typhimurium. It was found that the literature data on frequencies of contransduction in crosses with mutual substitution of selective and nonselective markers can be rationalized most accurately by assuming that the mean number of classes is equal to 2. An improved method for analysis of cotransduction data is proposed on the basis of our model and the results of calculation. The method relies on solving a set of algebraic equations for cotransduction frequencies of markers located within one phage length. The method allows a relatively precise determination of distances between markers, positions of transducing particle ends and deletion or insertion lengths. The approach is applied to the trp-cysB-pyrF and aroC-hisT-purF-dhuA regions of the Salmonella typhimurium chromosome.
提出并分析了一种非随机广义转导的数学模型。该模型考虑了任何给定标记的转导粒子类别的有限数量。推导了根据共转导频率数据估计标记间距离的方程，并给出了估计值的标准误差。所得关系显著依赖于转导片段的类别数量。该模型用于估计鼠伤寒沙门氏菌用噬菌体P22转导时给定标记的转导片段类别数量。结果发现，对于选择性和非选择性标记相互替换的杂交中的共转导频率的文献数据，通过假设类别平均数等于2能最准确地进行合理化解释。基于我们的模型和计算结果，提出了一种改进的共转导数据分析方法。该方法依赖于求解一组关于位于一个噬菌体长度内的标记共转导频率的代数方程。该方法能够相对精确地确定标记间的距离、转导粒子末端的位置以及缺失或插入长度。该方法应用于鼠伤寒沙门氏菌染色体的trp - cysB - pyrF和aroC - hisT - purF - dhuA区域。
