Molecular genetics and Early Embryonic Development Flashcards
What is the paradigm of development?
In every species and at every level of organization, complex structures are made by repeating a few basic themes with variations
What is differentiation?
cells begin to 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 dimensions does patterning occur in?
- Anterior-Posterior (top-bottom)
- Dorsal-Ventral (left-right)
- Proximal-Distal (front-back)
What are the differnet types of craniofacial abnormalities that concern dentistry?
- Malocclusion syndromes
– Pierre-Robin
– Treacher Collins
– Marfan syndrome - Craniofacial malformations
– Crouson
– Apert
– Pfeiffer
– Clefting syndromes (lip and palate) - Bone Mass Traits
– Sclerosteosis and van Buschem’s
– High Bone Mass and OPPG
– Paget’s Disease - Tooth Agenesis
- Tooth Movement
- Tooth Development Disorders
– Dentinogenesis Imperfecta
– Amelogenesis Imperfecta
What are the malocclusion abnormalities?
– Pierre-Robin
– Treacher Collins
– Marfan syndrome
What are the craniofacial malformations?
– Crouson
– Apert
– Pfeiffer
– Clefting syndromes (lip and palate)
What are bone mass trait abnormalities?
– Sclerosteosis and van Buschem’s
– High Bone Mass and OPPG
– Paget’s Disease
Craniofacial Anomalies Account
for ___ of All Congenital Defects
1/3
When is the greatest period of sensitivity to congenital defects?
3-8 weeks
What are the universal signaling pathways of animal development?
- receptor tyrosine kinase (RTK)
- TGFB superfamily
- Wnt
- Hedgehog
- Notch
What are the four important concepts of embryonic development?
- Universal Mechanisms of Animal Development
- Proteins can be substituted across species
- Inductive signaling
- Regional Determination
Multicellular organisms are enriched in ________ mediating cell interactions and gene regulation
proteins
Regulatory ____ defines the development program
DNA
What is asymmetric division?
sister cells born different
What is symmetric division?
sister cells become different as result of influences acting on them after their “birth”
What are the features of inductive signaling?
- 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 (week 3 in humans) transforms from a single cell layer (blastula) into the three primary germ layers:
– Ectoderm
– Endoderm
– Mesoderm
What process does this picture show?
sequential induction
What are the three primary germ layers?
– Ectoderm
– Endoderm
– Mesoderm
What direction does the primitive streak form?
anterior to posterior
(according to her but dr.cox says opposite)
Where does Hensen’s node form?
towards the anterior
Where do somites form?
towards the posterior
Race and ethnicity are social constructs or biological?
social constructions
What is race versus ethnicity?
Race: A socially defined category, based on real or perceived biological differences between groups of people.
Ethnicity: A socially defined category based on common language, religion, nationality, history , or another cultural factor
What is social epigenomics?
The impact of social and environmental factors and how that manifests biologically through genetic changes in response to those stresses
What percent of all live births exhibit some form of minor or major abnormality?
3%
How many craniofacial syndromes are there?
> 700 distinct syndromes
What is needed for craniofacial development?
- 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
- etc., etc., etc.
*very complicated
What are neural crest cells?
Embryonic cell population that is localized between the developing neural tube and the epidermis
What does it mean that some neural crest cells exhibit “stemness”?
they can give rise to multiple differentiated cell types
During formation of craniofacial structures the neural crest cells migrate through ________ to form the developing structures
restricted pathways
Cell migration is a ______ regulated process
tightly
How do neural crest cells migrate?
bilaterally
Over _____ genes identified that have mutations associated with tooth patterning, morphogenesis defects and cell differentiation defects
300
As a collective group craniofacial
genetic diseases are the ____ common
most
What are ectodermal dysplasias?
– >100 different disorders
– Commonly involves one or more of teeth, nails, skin, sweat glands and/or hair
What is hypodontia?
missing only a few teeth
What is oligiodontia?
missing more than 6 teeth, excluding third molars
What is anodontia?
absence of teeth
What are the genetic diseases of the dentition?
- Ectodermal dysplasias
- Tooth Agenesis
- Supernumerary Teeth
- Cleft Lip/Palate (OMIM lists 565 entries)
- Skeletal Diseases and the Dentition
What is microdontia?
one or more teeth appear
smaller
What is macrodontia?
one or more teeth grow faster and exceed average size
What drives tooth formation?
a homeobox
