GENE TRAPPING AND FUNCTIONAL GENOMICS

Classical genetics depends upon investigation of function by random de struction with little information on structure. Modern mapping using r andom polymorphisms, cloning and sequencing investigates structure wit hout function. The genome project with their rapid gene discovery are, however, redefining classical genetic approaches. The efficient trans lation of this wealth of new information into insights in biological f unction at molecular, cellular and organismal levels requires large-sc ale approaches to the generation of mutants. Gene trapping in embryoni c stem (ES) cells allows an efficient approach to the functional analy sis of the murine genome. The usually separate processes of gene disco very, mapping, the observation of the expression pattern and the mutan t phenotype in vivo, can be integrated by the use of an indexed librar y of insertionally mutated ES cell clones. It should be possible to ge nerate mutants for a large proportion of the genes of the mammalian ge nome.