Animal embryos need to specify different cell types, and the genetic functions that provide
such controls are easy to comprehend since they result in the formation of overtly …

Cell signaling plays a key role in the development of all multicellular organisms. Numerous
studies have established the importance of Hedgehog signaling in a wide variety of …

The zone of polarizing activity (ZPA) is a region at the posterior margin of the limb bud that
induces mirrorimage duplications when grafted to the anterior of a second limb. We have …

The identification of even the smallest human fetal bone can be vital to the success of a
criminal investigation or to the identification of the deceased. This book examines every …

The key role of vitamin A in embryonal development is reviewed. Special emphasis is given
to the physiological action of retinoids, as evident from the retinoid ligand knockout models …

Exposure of murine embryos to teratogenic doses of retinoic acid (RA) induced homeotic
transformations of vertebrae. Posterior transformations occurred along the complete body …

Mutation and expression studies have implicated the Wnt gene family in early
developmental decision making in vertebrates and flies. In a detailed comparative analysis …

MICE with targeted disruptions1 in Hox genes have been generated to evaluate the role of
the Hox complex in determining the mammalian body plan. This complex of 38 genes …

Serial sections of individual embryos of a staged series were hybridized with radioactive
probes for Sonic hedgehog, Hoxd-IO, Hoxd-? I, and Hoxd-72 Several embryos were …

Reciprocal inductive signals between the endoderm and mesoderm are critical to vertebrate
gut development. Sonic hedgehog encodes a secreted protein known to act as an inductive …