Polarity has a major influence on the mergence of the embryonic structures.

Figure 8shows the result of clustering the 99 differentiated embryonic structures that expressed at least two of the 1,388 genes.

Placodes are embryonic structures that give rise to structures such as hair follicles, feathers and teeth.

Variation in morphology and incomplete knowledge of the shape and position of various embryonic structures make computational approaches impracticable at present.

There is a need to have a specific name not only for the final developed embryonic structures but also for all the developmental intermediates that precede them.

The clustering organizes the embryonic structures in such a way that related structures are close together whereas unrelated ones are widely separated.

Many different species of insects have mouthparts derived from the same embryonic structures, indicating that the mouthparts are modifications of a common ancestor's original features.

These embryonic structures are the Wolffian and Müllerian ducts, also known as mesonephric and paramesonephric ducts, respectively.

Furthermore, gene-expression data can be used to quantify the relatedness of the various embryonic structures in terms of similarity in gene expression between them [ 29].

Cell marking experiments actually show that to be the case (Long, unpublished), thus we use the terms dorsal lip, blastopore, and yolk plug as names for the appropriate embryonic structures in this report.

PTCH1 is a member of the patched gene family and is the receptor for sonic hedgehog, a secreted molecule implicated in the formation of embryonic structures and in tumorigenesis.

Using this naming scheme we are able to describe the development of embryonic structures starting from anlage in statu nascendi at the cellular blastoderm stage through a series of developmental intermediates - anlage and primordia - to a differentiated embryonic structure.

Each of these parts of the blastocyst gives rise to different parts of the embryo; the inner cell mass gives rise to the embryo proper, while the trophectoderm and primitive endoderm give rise to extra embryonic structures that support growth of the embryo.

In this case, the zones of information were thought to be located in two embryonic structures, one called the notochord, a stiff rod that serves as the developing creature's temporary backbone, and the other called the floor plate, a bulge of tissue that eventually gives rise to the adult spinal cord.

In the zebrafish, MED12 defects cause maldevelopment of vertebrate embryonic structures such as the neural crest, which would alter function of the autonomic and peripheral nervous systems; and they also cause malformations of cell types serving as precursors to cartilage and bone, such as osteocytes.

Originating from the lateral ganglionic eminence, one of the three embryonic structures that eventually become specific parts of the brain, the sub-ventricular zone (SVZ) is a group of cells that develop along the surface of the ventricular layer of the brain, following the creation of the cortical plate in embryos.