T-DNA as an Insertional Mutagen in Arabidopsis

作者：Patrick J. Krysan, Jeffery C. Young, Michael R. Sussman · 发表于：The Plant Cell · 年份：1999 · DOI：10.1105/tpc.11.12.2283 · 被引用次数：720 · 研究领域：Plant tissue culture and regeneration、Plant Molecular Biology Research、Plant Genetic and Mutation Studies

Forward genetics begins with a mutant phenotype and asks the question “What is the genotype?” that is, what is the sequence of the mutant gene causing the altered phenotype? Reverse genetics begins with a mutant gene sequence and asks the question “What is the resulting change in phenotype?” These two approaches are fundamentally different, and whereas forward genetics has been in operation for more than a century, the recent avalanche of complete genome sequences has only now created the opportunity for pursuing reverse genetics in an exhaustive and complete manner. Gene knockouts, or null mutations, are important because they provide a direct route to determining the function of a gene product in situ. Most other approaches to gene function are correlative and do not necessarily prove a causal relationship between gene sequence and function. For example, DNA chips provide an exciting means to discover conditions under which gene expression is regulated on a genomewide scale (DeRisi et al., 1997; Wodicka et al., 1997; Singh-Gasson et al., 1999). However, because factors other than mRNA level alone determine the activity of a gene product in situ, expression studies, even when done on a genomewide scale, cannot prove a causal relationship. By contrast, the availability of a null mutation for the gene of interest allows one to directly monitor the effect this deficiency has on the organism’s ability to function. There are many ways to implement targeted mutagenesis so as to co...