Lecture 15 - Segment specification in vertebrates Flashcards
1
Q
What is the fate of somites?
A
- Vertebrae and ribs
- Dermis of the dorsal skin
- The skeletal muscles of the back, body wall, and limbs
2
Q
How is the fate of tissue within a
somite controlled?
A
By signals from adjacent
tissue
3
Q
True or False? Somites do not already contain positional
information prior to their formation
A
- False
- They do
4
Q
What determines the difference between somites?
A
- Mainly Hox genes do
- 3’ genes affect the anterior structures
- 5’ affect more posterior structures
5
Q
What effect can a high concentration of retinoic acid have on hox genes?
A
- Causes a misexpression of hox genes
- Longer exposure
to retinoic acid produces expression of more posterior
patterns
6
Q
What happens when retinoic acid binds and activates its receptor?
A
The downstream target genes are transcribed
7
Q
True or False? Retinoic acid regulates expression of HOX
genes
A
True
8
Q
How does retinoic acide activate Hox genes?
A
Sequentially (in sequence)
