Chapter 6 Differential Gene Activity in The Pre-And Postimplantation Mammalian Embryo

Abstract

This chapter describes some of the correlations between the appearance of the various classes of macromolecules and the anatomical features that develop during mammalian embryogenesis. Differential gene activity in the pre- and early post-implantation mammalian embryo results in the expression of certain parts of the genotypic potential to create a phenotypic form. The morphological development of an embryo is characterized in terms of the ontogenetic landmarks for many years. A delineation of the pattern of ribonucleic acid (RNA) transcription during development seem to be one of the first steps in any understanding of the regulation of gene action during embryogenesis. The work described in the chapter is limited to the pre- and post-implantation development of the mouse and rabbit. A more detailed review of the biochemistry of early mammalian development is discussed in the chapter. The biochemistry of embryogenesis in an increasing number of invertebrate and amphibian species are described in the chapter. This chapter describes the protein moieties that produce a distinct cellular phenotype and their regulation. The genetic and biochemical evidence for the changing patterns of gene activity during the early mammalian development is discussed this chapter. The timing and the onset of RNA synthesis in preimplantation embryos, the diversity of the genetic information contained in the RNA transcripts, and the relationship of these processes to the other biochemical events in the embryo are also discussed in this chapter.