Molecular Genetics & Early Embryonic Development Flashcards
Dr. Erin Bumann
Cells begin to form specific & specialized structures
Differentiation
Cell divisions that form more cells with identical functions as the parent cells
Growth
What are the three stages of embryonic decelopment?
- Differentiation
- Growth
- Patterning
Cells produced by cleavage get organized into layers and groups of cell masses through what as known as gastrulation
Patterning
The process of patterning in which cells get organized into layers and groups of cell masses occurs through:
Gastrulation
Patterning needs to occur in three dimensions, these include:
- Anterior-posterior (top-bottom)
- Dorsal-ventral (left-right)
- Proximal-distal (front-back)
Where does dentistry fit into the continuum of patterning & embryonic development?
- Malocclusion syndromes
- Craniofacial malformations
- Bone mass traits
- Tooth agenesis
- Tooth movement
- Tooth development disorders
The following conditions are all considered:
Pierre-Robin
Treacher Collins
Marfan Syndrome
Malocclusion syndromes
The following conditions are all considered:
-Crouson
-Apert
-Pfieffer
-Clefting syndromes (lip & palate)
Craniofacial malformations
The following conditions are all considered:
-Sclerosterosis and Van Buschem’s
-High bone mass and OPPG
-Paget’s disease
Bone mass traits
Tooth agenesis can be described as:
Missing teeth
The following conditions are considered:
-Dentintogenesis imperfecta
-Amelogenesis imperfecta
Tooth development disorders
Amelogenesis imperfecta can be described as:
Tooth development disorders affecting the enamel
Craniofacial anomalies account for:
1/3 of all congenital defects
Describe the susceptibility to teratogenesis during 0-2 weeks:
Not sensitive; high rate of lethality may occur
Describe the susceptibility to teratogenesis during 3-8 weeks:
Period of greatest sensitivity; Each organ system also has a period of peak sensitivity
Describe the susceptibility to teratogenesis during 9-38 weeks:
Decreasing sensitivity; Period of functional maturation
Developmental time period in which the face is forming:
3-8 weeks
List four important concepts of embryonic development:
- Universal mechanisms of animal development
- Proteins can be substituted across species
- Inductive signaling
- Regional determination
What are the five signaling pathways that species share in common?
-Receptor Tyrosine Kinase (RTK)
-TGF-Beta Superfamily
-WNT Signaling
-Hedgehog Signaling
-Notch Signaling
Multicellular organisms are enriched in proteins mediating:
Cell interactions & gene regulation
Proteins can be _______ across species
Substituted
________ defines the developmental program of an organism
Regulatory DNA
An important concept of embryonic development is ______ versus _____ cell division
Asymmetric versus symmetric cell division
Gradients reflective of the balance between positive & inhibitory inductive signals; sequential inductions
Inductive signaling & morphogens
Division in which sister cells are born different:
Asymmetric division
Division in which sister cells become different as a result of influences acting on them after their birth:
Symmetric division
Inductive signaling is characterized by:
- Starting point (cell or cell cluster)
- Cell-cell signaling
- Cell signaling cascades
- Acts over great distances
Early developmental process in which the embryo (week 3 in humans) transforms from a single cell layer (blastula) into the three primary germ layers:
Gastrulation
When does the process of gastrulation occur?
3 weeks (in humans)
Gastrulation transforms a single cell layer (______) into three ______
Blastula; primary germ layers
What are the primary germ layers formed from the blastula through gastrulation?
- Ectoderm
- Endoderm
- Mesoderm
Forms towards the anterior following gastrulation:
Hensen’s node
Forms from anterior to posterior following gastrulation:
Primitive streak
Following gastrulation, we get ______ formation towards the anterior and _____ formation towards the posterior
Head; somite
Race and ethnicity are considered _____ meaning that they do not exist _____
Social constructions; biologically
A socially defined category, based on real or perceived biological differences between groups of people:
Race
A socially defined category based on common language, religion, nationality, history or another cultural factor:
Ethnicity
Misappropriates the authority of science and undermines it by converting it into a social weapon:
Scientific racism
The impact of social and environmental factors and how that manifests biologically through genetic changes in response to those stresses:
Social epigenomics
Around how many distinct craniofacial syndromes exist?
More than 700
Craniofacial syndromes are a significant cause of:
Infany mortality
___% of all live births exhibit some form of minor or major craniofacial abnormality
3%
Embryonic cell population that is localized between the developing neural tube and the epidermis:
Neural crest cells
Neural crest cells are an embryonic cell population located between:
The developing neural tube & the epidermis
Some neural crest cells exhibit _____, meaning that they can give rise to multiple differentiated cell types
Stemness
In the formation of craniofacial structures (and many other structures), the _______ migrate through restricted pathways to form the developing structures
Neural crest cells
Cell migrates is a tightly regulated process and the NCCs receive cues such as _____ & _____ that restrict their movement and determine fate
Morphogens & growth factors
Over ____ genes have been identified that have mutations associated with tooth patterning, morphogenesis defects and cell differentiation defects
300 genes
As a collective group ____ diseases are the most common
Craniofacial genetic diseases
List the five main categories of genetic diseases of the dentition:
- Ectodermal dysplasias
- Tooth agenesis
- Supernumerary teeth
- Cleft lip/palate
- Skeletal diseases and the dentition
-Greater than 100 different disorders
-Commonly involves one or more of teeth, nail, skin, sweat glands &/or hair
Ectodermal dysplasias
List the three types of tooth agenesis:
- Hypodontia
- Oligodontia
- Anodontia
Missing only a few teeth, common type of tooth agenesis:
Hypodontia
Missing more than 6 teeth, excluding third molars, more severe form of agenesis:
Oligodontia
Absence or complete lack of teeth:
Anodontia
Form of tooth agenesis in which one or more teeth appear smaller:
Microdontia
Form of tooth agenesis in which one or more teeth grow faster and exceed average size:
Macrodontia
Code that drives homeobox formation and is extremely important that it results in the correct schematic:
Homeobox code
