Establishment of the body plan study notes

Drosophila Axis Development and Homeotic Genes
Drosophila A/P and D/V Axis Development: Maternal Genes
Maternal Genes -
- Maternal effect genes are expressed in the oocyte and play crucial roles
in establishing the anterior-posterior (A/P) and dorsal-ventral (D/V) axes
during Drosophila embryogenesis.
A/P Axis Development -
Bicoid (bcd)
-Function- Maternally deposited mRNA gradient along the q
A/P axis.
-Effect- Controls anterior development; higher concentration in
anterior regions leads to the specification of head and thorax
structures.
Hunchback (hb)-
- Function - Transcription factor regulated by Bicoid.
- Effect - Expressed in anterior regions, involved in anterior
patterning.
Caudal (cad)-
- Function - Maternally provided mRNA gradient along the A/P
axis.
Effect -Expressed in posterior regions, involved in posterior
patterning.
D/V Axis Development -
Dorsal (dl)-
-Function- Maternally deposited nuclear gradient.
-Effect - Forms a gradient along the D/V axis; high levels
ventrally and low levels dorsally.
Dorsal/Ventral Patterning - Dorsal gradient activates or represses
target genes, establishing the ventral and dorsal regions of the
embryo.
Drosophila A/P and D/V Axis Development: Zygotic Genes