Chapter 19 DNA Transformation

Publisher Summary This chapter discusses DNA transformation. DNA transformation assays in a whole organism provide experimental links between molecular structure and phenotype. Experiments with transgenic Caenorhabditis elegans start in general with the injection of DNA into the adult gonad. Effects on phenotype or gene expression patterns can be analyzed either in F1 progeny derived from the injected animals or in derived transgenic lines. Germ-line transformation has been achieved by microinjection of DNA directly into oocyte nuclei or by microinjection of DNA into the cytoplasm of the hermaphrodite syncytial gonad. Three forms of heritable DNA transformation have been observed in C. elegans are: (1) extra chromosomal transformation; (2) non-homologous integration; and (3) homologous integration. Setting up microinjection in a laboratory already equipped for C. elegans genetics and molecular biology requires a modest investment in space and money. A separate easily scoreable marker gene to identify transformed animals can be extremely useful in a variety of injection experiments. The propensity for injected DNA molecules to recombine with each other generally allows one to coinject the selectable marker with a DNA segment to be tested for activity.