GSK-3 Protein that negatively regulates Wnt signaling

ingression Movement of cells by becoming mesenchymal and internalizing

karyokinesis Division of nucleus without cellular division

Gurken Ligand active in the developing Drosophila oocyte that specifies both A/P and D/V axes

notochord Structure that forms from the chordamesoderm

holoblastic Cleavage in which entire embryo divides

Pair-rule Type of patterning gene that is expressed in alternate segments in Drosophila embryo

epithelial Type of cell with tight associations with surrounding tissue

archenteron Primitive gut

zona pellucida Mammalian egg structure that must be removed before implantation

primitive groove Name for the chick blastopore (not the DLB)

neural tube Structure induced to form by the notochord

Nanos Posteriorizing protein in Drosophila embryo

regulative Type of development that Xenopus embryos undergo (with regard to specification)

BMP-4 Molecule that specifies the ventral side of the amphibian embryo

spina bifida Failure of the posterior region of the neural tube to close

isolecithal Type of egg with very little yolk

gray crescent Region of amphibian embryo opposite site of sperm entry

Cerberus and frz-b Two Wnt inhibitors that are secreted, extracellular proteins