THE EFFECTS OF GENOTYPE AND CELL ENVIRONMENT ON MELANOBLAST DIFFERENTIATION IN THE HOUSE MOUSE

Abstract

HE FOUNDATION of all embryonic development consists of the processes T by which cells become differentiated from each other and from their common progenitors. These processes of cellular differentiation, though basic to an understanding of embryogeny, remain largely unknown, although two major factors are generally recognized as important in governing the course of cell development. First, the genetic makeup of cells defines the limits and the potentialities of their development, and second, the diverse cellular environments of the embryo elicit the specific developmental responses in cells which lead to their maturation into the wide variety of cell types that characterizes the adult. These local and highly specific cell environments are produced by cellular activity and are constantly changing as the responsible cells change. Thus a continually evolving dynamic interchange between embryonic cells directs their differentiation into specialized adult cells and finally into senescent cells incapable of sustaining the life of the organism.