Molecular Genetics and Early Embryonic Development Flashcards
What are the stages of embryonic development
- differentiation
-growth - patterning
what is differentiation
cells form specific and specialized structures
what is growth
cell divisions that form more cells with identical functions as the parental cell
what is patterning
cells produced by cleavage get organized into layers and groups of cell masses through what is known as gastrulation
what 3 dimensions does patterning need to occur in
-anterior posterior
- dorsal ventral
- proximal and distal
what are the malocclusion syndromes
-pierre robin
-treacher collins
-marfan syndrome
what are the craniofacial malformations
-crouson
- apert
- pfeiffer
-clefting syndromes
what are the bone mass traits
-sclerosteosis and van Buschem’s
- high bone mass and OPPG
- Pagets disease
craniofacial anomalies account for ~______ of all congential defects
1/3
when is the risk highest for teratogenesis and lowest
3-8 weeks is the highest, 9-38 is the lowest
what is meant by universal mechanisms of animal development
species share signal proteins and receptors in common
what defines the development program
regulatory DNA
what are multicellular organisms enriched with
proteins mediating cell interactions and gene regulation
what is inductive signaling and morphogens
gradients reflective of a balance between postive and inhibitory signals or sequential induction
what is the difference between asymmetric and symmetric division
- asymmetric division- sister cells born different
- symmetric division- sister cells become different as a result of influences acting on them after their birth
describe inductive signaling
- theres a starting point: cell or cell cluster
- cell- cell signaling
- cell signaling cascades
- acts over great distances
what is gastrulation
early developmental process in which the embryo transforms from a single cell layer (blastula) into the three primary germ layers
what are the three primary germ layers
ectoderm, endoderm, mesoderm
race and ethnicity are _____. they do not exist ____.
social constructions; biologically
what is a race
a socially defined category based on real or perceived biological differences between groups of people
what is ethnicity
a socially defined category based on common language, religion, nationality, history or another cultural factor
what are social epigenomics
the impact of social and environmental factors and how that manifests biologically through genetic changes in response to those stresses
the stresses dont change the ______ but they affect _____
underlying human genome; gene expression
what percentage of all births exhibit some form of a craniofacial syndrome
3%
what does craniofacial development include
- neural tube development and closure
- formation of ectoderm, somites, mesoderm and other cell masses
- neural crest cell development, differentiation and migration
- tissue- tissue interactions
- tissue specific patterns of gene expression
- reciprocal induction.
- growth and mineralization of bones and teeth
- neural development
- muscle development
what are neural crest cells
embryonic cell population that is localized between the developing neural tube and the epidermis
what do some neural crest cells exhibit and what is this
stemness- they can give rise to multiple differentiated cell types
how do neural crest cells migrate to form developing structures
through restricted pathways under a tightly regulated process and receive cues such as morphogens and growth factors that restrict their movement and determine fate
what are the 5 key development signaling pathways
-RTK
- TGF beta
- Wnt
- Hedgehog
- Notch
how many genes have been identified that have mutations associated with tooth patterning, morphogenesis defects and cell differentiation defects
300
what are ectodermal dysplasias and how many are there
- over 100 different disorders
- commonly involves one or more teeth, nails, skin, sweat glands and/or hair
what is hypodontia
missing only a few teeth
what is oligodontia
missing more than 6 teeth excluding third molars
what is anodontia
absence of teeth
what is microdontia
one or more teeth appear smaller
what is macrodontia
one or more teeth grow faster and excess average size
what are the key signaling pathways in tooth development
oral ectoderm -> dental mesenchyme -> dental placode -> condesned dental mesenchyme -> enamel knot -> dental papilla
what drives tooth formation
homeobox code
