Genetics of Development Flashcards
A cell can be removed in what phase during pre-implantation diagnosis?
Morula
What is the first axis visible in the embryo?
anterior-posterior
What structure defines the anterior posterior axis?
primitive streak
What does the primitive streak mark?
Where ectodermal cells invade the space between the epiblast and the hypoblast
What does the ectoderm form?
skin and nervous system
What does mesoderm form?
bone, muscle and most internal organs
What will the endoderm form?
cells of the gut and lung epithelium
Where is the node located?
at the anterior end of the primitive streak
What is the function of noggin and chordin?
to induce dorsal development
Where are noggin and chordin released from?
the node
Where is Shh released from?
notochord
What is the function of Shh?
right/left asymmetry
What is situs inversus?
where internal organs are a mirror image of what is normally found
What is the condition called where the organs are randomized in their location?
situs ambiguus
What is situs ambiguus usually accompanied with?
heart defects
What is the function of the homeobox (HOX) genes?
patterning along the anterior/posterior axis
What is patterning?
determining what part of the embryo divides into specific parts
What are malformations?
an intrinsic abnormality in the developmental process
What do deformations result from?
extrinsic influence on the development of an organism
What do disruptions result from?
destruction of developing tissue
What is a sequence?
a cascade of events resulting from a single anomaly
What is a syndrome?
when all disease phenotypes are caused by a single defect
What do defects arising between 1-4 weeks development produce?
multiple organ abnormalities
VACTERL
What is a major risk factor for VACTERL defects?
maternal diabetes
What do abnormalities occurring from week 5 to 8 affect?
specific organs to produce specific anomalies
What are cells during the regulative phase?
functionally equivalent
A morula is in what phase of development?
regulative
A loss of a cell in the mosaic phase results in what?
loss of tissue the cell was destined to become
The primitive streak is formed by what type of cells?
Ectoderm
What is the first visible axis in the embryo?
anterior/posterior axis
What is the anterior/posterior axis defined by?
primitive streak
What two proteins are secreted from the node?
noggin and chordin
What are the functions of noggin and chordin?
induce dorsal development in a concentration dependent manner
Where is the node located?
anterior end of primitive streak
What protein is responsible for left/right asymmetry?
Shh
Where is Shh secreted from?
notochord
Asymmetric expression of Shh leads to left sided expression of what protein?
Nodal
A defect in left/right formation is referred to as what?
situs inversus
What describes a condition in which organs are randomized in their location?
situs ambiguus
Patterning along the anterior/posterior axis is controlled by what family of genes?
HOX
What causes malformations?
intrinsic abnormality
What causes deformations?
extrinsic influence
What causes disruptions?
result from the destruction of developing tissue
Isolated anomalies affect what?
a single body region
What is a sequence?
cascade of events starting from an anomaly
What do syndromes affect?
several body regions
What kind of inheritance do syndromes possess?
Mendelian
When do abnormalities that affect single organ systems originate?
week 5 to 8
Defects in the weeks of 1-4 can be characterized by what acronym?
VACTERL
What maternal behavior is a risk for VACTERL?
diabetes
In order, what is the order of the most common congenital malformations?
heart defects, pyloric stenosis, neural tube defects, orofacial clefts, clubfoot
Where is the node located?
anterior end of primitive streak
Where are noggin and chrodin secreted from? What is their function?
the node
induce dorsal development
Where is Shh secreted from? What is its function?
notochord
right/left development
What gene is required for the formation of the primitive streak?
Nodal
What two conditions can arise from defects in right/left development?
situs inversus and situs ambiguus
What is the function of the HOX genes?
to develop patterning along the anterior/posterior axis
What disease does the Philadelphia Chromosome cause?
acute myeloid leukemia
