©THEBRIGHTSTARS 2024
EEB 184: Exam #2 Study Guide.
Proximal-Distal
Anterior-Posterior
Dorsal-Ventral - answer✔(pic)
3 Segments of Adult Limb - answer✔-Stylopod
-Zeugopod (forearm)
-Autopod (hand/foot)
Hox Genes in Limb Development - answer✔-Used in patterning body axis (influences where)
-forelimb development & hindlimb development
-controls limb PLACEMENT along body axis
How would you expect forelimb outgrowth to be impacted by shift in Hox genes (Mutant)?
(W.T. - aligned & shifted Hox gene expression (FLANK))
(Mutant - aligned & parallel Hox gene expression (FLANK)) - answer✔-Little/no limb
outgrowth
-FLANKS repressing eachother
-becomes snake (python)
Limb Induction - answer✔combination of Hox genes working to make a limb
Limb Outgrowth: Cells - answer✔Fgf10 (fibroblast growth factor
SHH (sonic hedgehog)
Fgf4 + Fgf8
Fgf8: becomes AER
Limb Development: Zones - answer✔(pic)
AER - answer✔-drives cell proliferation & regulates limb outgrowth
-essential to limb growth
, ©THEBRIGHTSTARS 2024
What would you expect to happen if AER was removed before outgrowth began? - answer✔-
Autopod & Zeugopod would NOT form but stylopod
-Stylopod still forms since hard to remove ERD in time (see it = too late)
AER & ZPA - answer✔-interact to regulate limb outgrowth & patterning
-ZPA secrets SHH protein
Assume you had 2nd ZPA to anterior side of limb. What phenotype would you expect in
resulting chick limb? - answer✔Limb structures would be repeated in mirror-like pattern
In mouse #1, Shh knocked out during limb development. What would happen if a mutation was
instead introduced into the protein-coding region of Shh? - answer✔-Embryo would display
deformations EVERYWHERE in many organ systems, including limb
-since mutation in all cells - not just in limb development!
Earlier Shh was removed = _?_ digits formed - answer✔fewer
Limb Development: Shh - answer✔-keeps limb growing out
-big role in proliferation & determining # of digits & patterning
Shh & Cell Death Correlation - answer✔-Shh not present = cell death inc.
-Shh present = cell death dec.
Interdigital tissue regression - answer✔BMP: cell death to rid of webbed fingers
4 Mechanisms of Evo-Devo - answer✔Heterotopy
Heterochrony
Heterotypy
Heterometry
Heterotopy - answer✔change in location
-ex) duck/bat/dolphin/whales flippers
-duck: gremlin repress BMP
-bat/dolphin/whale: gremlin&FGFs represses BMP
-change in location: gremlin/FGFs
-ducks = only gremlin!
Heterochrony - answer✔change in time
EEB 184: Exam #2 Study Guide.
Proximal-Distal
Anterior-Posterior
Dorsal-Ventral - answer✔(pic)
3 Segments of Adult Limb - answer✔-Stylopod
-Zeugopod (forearm)
-Autopod (hand/foot)
Hox Genes in Limb Development - answer✔-Used in patterning body axis (influences where)
-forelimb development & hindlimb development
-controls limb PLACEMENT along body axis
How would you expect forelimb outgrowth to be impacted by shift in Hox genes (Mutant)?
(W.T. - aligned & shifted Hox gene expression (FLANK))
(Mutant - aligned & parallel Hox gene expression (FLANK)) - answer✔-Little/no limb
outgrowth
-FLANKS repressing eachother
-becomes snake (python)
Limb Induction - answer✔combination of Hox genes working to make a limb
Limb Outgrowth: Cells - answer✔Fgf10 (fibroblast growth factor
SHH (sonic hedgehog)
Fgf4 + Fgf8
Fgf8: becomes AER
Limb Development: Zones - answer✔(pic)
AER - answer✔-drives cell proliferation & regulates limb outgrowth
-essential to limb growth
, ©THEBRIGHTSTARS 2024
What would you expect to happen if AER was removed before outgrowth began? - answer✔-
Autopod & Zeugopod would NOT form but stylopod
-Stylopod still forms since hard to remove ERD in time (see it = too late)
AER & ZPA - answer✔-interact to regulate limb outgrowth & patterning
-ZPA secrets SHH protein
Assume you had 2nd ZPA to anterior side of limb. What phenotype would you expect in
resulting chick limb? - answer✔Limb structures would be repeated in mirror-like pattern
In mouse #1, Shh knocked out during limb development. What would happen if a mutation was
instead introduced into the protein-coding region of Shh? - answer✔-Embryo would display
deformations EVERYWHERE in many organ systems, including limb
-since mutation in all cells - not just in limb development!
Earlier Shh was removed = _?_ digits formed - answer✔fewer
Limb Development: Shh - answer✔-keeps limb growing out
-big role in proliferation & determining # of digits & patterning
Shh & Cell Death Correlation - answer✔-Shh not present = cell death inc.
-Shh present = cell death dec.
Interdigital tissue regression - answer✔BMP: cell death to rid of webbed fingers
4 Mechanisms of Evo-Devo - answer✔Heterotopy
Heterochrony
Heterotypy
Heterometry
Heterotopy - answer✔change in location
-ex) duck/bat/dolphin/whales flippers
-duck: gremlin repress BMP
-bat/dolphin/whale: gremlin&FGFs represses BMP
-change in location: gremlin/FGFs
-ducks = only gremlin!
Heterochrony - answer✔change in time
