What good is recombinant DNA if you're not a molecular biologist?

Site directed tumorigenesis combines many techniques of modern biology: DNA manipulation and splicing, gene structure and function and transgenic animals with the more "classical" disciplines of cancer research and cell biology. Is this of any use to someone interested in how a whole mammal functions? Or is this merely an attempt to explain the forest by studying the leaves? Recently, site directed tumorigenesis was used to develop a clonal cell line that may help answer some important questions in reproductive endocrinology. This essay outlines some of these questions, briefly explains how this cell line was produced and tries to describe some of the ways in which these cells will help us answer the questions.