Developmental Biology

The process by which a less specialized cell becomes a more specialized cell type with a distinct structure and function. Differentiation is driven by differential gene expression, in which specific genes are activated or silenced by transcription factors, epigenetic modifications, and signaling molecules.

The biological process that causes an organism or tissue to develop its shape. It involves coordinated cell movements, changes in cell shape, selective adhesion, and controlled cell proliferation and death, all guided by molecular signals and physical forces.

A process in which one group of cells (the inducer) signals to an adjacent group of cells (the responder), causing the responder to change its developmental fate. Induction is a primary mechanism for generating cell diversity in the embryo.

The process by which cells acquire positional identities that lead to the spatial organization of differentiated cell types within a tissue or organism. Morphogen gradients, where signaling molecules are distributed in concentration gradients, are a central mechanism.

Concentration gradients of signaling molecules (morphogens) that provide positional information to cells. Cells respond to different threshold concentrations by activating distinct gene expression programs, thereby acquiring different fates depending on their distance from the morphogen source.

Stem cells are undifferentiated cells capable of self-renewal and differentiation into specialized cell types. Potency ranges from totipotent (able to form all cell types including extraembryonic tissues), to pluripotent (all embryonic cell types), multipotent (several related types), and unipotent (one type only).

A critical phase of early embryonic development during which the single-layered blastula reorganizes into a multilayered structure called the gastrula, establishing the three primary germ layers: ectoderm, mesoderm, and endoderm.

Hox genes are a family of transcription factor genes containing a conserved DNA sequence called the homeobox. They specify the identity of body segments along the anterior-posterior axis and are expressed in a colinear fashion, with their chromosomal order matching their expression domain along the body axis.

A genetically regulated process of controlled cell death essential for sculpting tissues, eliminating unwanted cells, and maintaining homeostasis during development. It involves activation of caspase enzymes that dismantle the cell from within.

The establishment of the primary body axes — anterior-posterior, dorsal-ventral, and left-right — early in embryonic development. Maternal factors, cortical rotation, and signaling centers work together to break the initial symmetry of the egg.