Developmental Biology Glossary

A thickened epithelial structure at the distal tip of the limb bud that secretes FGFs to drive limb outgrowth.

Genetically controlled programmed cell death involving caspase activation, used to sculpt tissues and eliminate unwanted cells.

The establishment of the primary body axes (anterior-posterior, dorsal-ventral, left-right) during early development.

An early embryonic stage consisting of a hollow sphere of cells formed after cleavage divisions.

A signaling molecule in the TGF-beta superfamily that patterns the dorsal-ventral axis and promotes epidermal and bone fates.

The ultimate differentiated state that a cell or its progeny will adopt during normal development.

Rapid mitotic divisions of the zygote that produce smaller blastomeres without increasing total embryo volume.

The ability of a cell or tissue to respond to a specific inductive signal during a limited developmental window.

The commitment of a cell to a particular developmental fate that persists even if the cell is moved to a new environment.

The outermost germ layer, giving rise to the epidermis, nervous system, and neural crest derivatives.

The innermost germ layer, giving rise to the lining of the gut, lungs, liver, pancreas, and thyroid.

Heritable changes in gene expression that do not involve alterations to the DNA sequence, including DNA methylation and histone modification.

The process by which the blastula reorganizes into a multilayered embryo with ectoderm, mesoderm, and endoderm.

The three primary tissue layers (ectoderm, mesoderm, endoderm) established during gastrulation from which all adult tissues derive.

A mutation-driven developmental change in which one body structure is replaced by another, typically caused by Hox gene misexpression.

A conserved family of transcription factor genes that specify segment identity along the anterior-posterior body axis.

A cell-cell signaling interaction in which one tissue directs the developmental fate of an adjacent tissue.

The middle germ layer, giving rise to muscle, bone, connective tissue, the circulatory system, and kidneys.

A signaling molecule that forms a concentration gradient and specifies different cell fates at different threshold concentrations.

The process by which organized tissue and organ shapes are generated through cell movement, growth, adhesion, and death.

A multipotent, migratory cell population arising at the neural plate border that gives rise to diverse cell types including peripheral neurons and craniofacial cartilage.

The embryonic process in which the neural plate folds and fuses to form the neural tube, precursor to the central nervous system.

A juxtacrine signaling pathway where transmembrane receptors on one cell interact with ligands on adjacent cells, mediating lateral inhibition and cell fate decisions.

A three-dimensional, self-organizing culture derived from stem cells that recapitulates key structural and functional aspects of an organ.

Describing a cell capable of giving rise to all cell types of the body but not extraembryonic tissues such as the placenta.