counting mutagenized genomes and optimizing genetic screens in caenorhabditis elegans计数诱变处理基因组和遗传优化屏幕在线虫.pdfVIP

Counting Mutagenized Genomes and Optimizing Genetic Screens in Caenorhabditis elegans Shai Shaham* Laboratory of Developmental Genetics, The Rockefeller University, New York, New York, United States of America In genetic screens, the number of mutagenized gametes examined is an important parameter for evaluating screen progress, the number of genes of a given mutable phenotype, gene size, cost, and labor. Since genetic screens often entail examination of thousands or tens of thousands of animals, strategies for optimizing genetics screens are important for minimizing effort while maximizing the number of mutagenized gametes examined. To date, such strategies have not been described for genetic screens in the nematode Caenorhabditis elegans. Here we review general principles of genetic screens in C. elegans, and use a modified binomial strategy to obtain a general expression for the number of mutagenized gametes examined in a genetic screen. We use this expression to calculate optimal screening parameters for a large range of genetic screen types. In addition, we developed a simple online genetic-screen-optimization tool that can be used independently of this paper. Our results demonstrate that choosing the optimal F2-to-F1 screening ratio can significantly improve screen efficiency. Citation: Shaham S (2007) Counting Mutagenized Genomes and Optimizing Genetic Screens in Caenorhabditis elegans. PLoS ONE 2(11): e1117. doi:10.1371/journal.pone.0001117 INTRODUCTION we demonstrate that for at least one major screen class, the Poisson The identification of mutant animals is usually the first step in the approximation leads to large errors. genetic analysis of a biological process. In animals amenable to Using the generalized expression described above, we solve genetic study, such mutants are commonly id