Gene Expression Controls Development Flashcards
Development
growth from single cell to mature individual through tissue differentiation
Changes in Gene Expression
triggered by chemical signals: changes in cell division rates/cell shape/cell-cell interaction/body axes
Body Axes
after axes are formed: developmental genes are expressed depending on location: signal position or establish cell identity
Blastocyst
Inner cell mass: form embryo/divides little, trophoblast: form placenta/divides fast,
implantation occurs: ~ 6 days post fertilization
Embryonic Stem Cells
isolated from inner cell mass: differentiate into specialized tissue types: greatest differentiation potential
Stem Cells
Capable of self-renewal, high proliferative potential, differentiation potential
Germline stem cells
gametes used for reproduction (sperm/egg)
Cord Blood Stem cells
Umbilical cord, blood cell stem cells/mesenchymal cells (bon/heart muscle/brain/liver tissue etc)
Adult Stem Cells
Found in different tissues throughout life span of organism: specialized for given organ, may be multipotent/unipotent, hard to ID/isolate, limited lifespan
Cell fate
established early in embryogenesis, fate depends on position within embryo, fate realized: steps mediated by specific regulatory proteins/cell-cell signals that alter gene expression
Induction
initiates tissue/organ formation, influence of group of cells upon another (optic cup –> lens formation –> cornea formation): chemical signals controlled
Toolkit genes
determine what is built/where, encode signals (ligands), receptors, transcription factors: (ligand -> receptor -> TF -> switches on protein production) switches genes that either construct organs/signals that tell cells what to do
Homeotic Genes
“Master control genes” that regulate many other genes/direct embryonic development:
Hox genes
switch on genes that determine what is made, switched on by position
Heterochrony
differences in timing/duration of gene expression
