Chapter 34 Mosaic Analysis Using FLP Recombinase

Publisher Summary This chapter discusses the use of clones of cells to study the phenotype of mutations in isolated patches of tissue, within an otherwise wild-type. This application of mosaics is especially useful for the study of genes that are essential for the viability of the whole organism because specifically removing their function in isolated clones does not necessarily impair overall survival. In these experiments the effects of mutations, lethal or otherwise, can be examined on both the mutant and surrounding wild-type tissue. The chapter describes the use of FLP recombinase and novel cell markers to greatly facilitate this type of analysis and, in addition, allows the rapid isolation of mutations, including lethals, which affect the development and function of the fly. The methods have greatly improved the efficacy of traditional mosaic analysis and make it feasible to use this technique to screen for novel mutations. However, if certain tissues are made homozygous for some lethal mutations the flies will die. In this case, a high frequency of mosaicism may result in unacceptable mortality. If survival following heatshock is low, it is suggested that the duration of the heat treatment should be reduced.