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Unformatted text preview: rsors.
d) vegetal hemisphere cells in this region receive signals from
overlying animal hemisphere cells and become mesodermal precursors. b) die. The dorsalizing factors that induce formation of the
organizer in Xenopus embryos
a) arise at the point of sperm entry and move across the
animal pole toward the organizer region.
b) arise at the vegetal pole and move dorsally toward the
c) arise at the animal pole and move dorsally toward the
d) are present in ventral vegetal cells before the
e) are present in dorsal animal cap cells before the
organizer forms. What will happen to the dorsal /ventral patterning of the
Xenopus embryo under the following conditions?
If GSK-3 is overexpressed
throughout the embryo , the embryo
b. dorsalized Which of these statements is true in the Xenopus embryo?
a) The organizer induces formation of neural ectoderm
by locally inhibiting an inhibitor of neural
cell fates in the animal cap.
b) The organizer induces formation of neural ectoderm
by locally inducing animal cap cells that
would otherwise adopt epidermal fates.
c) The organizer moves during gastrulation toward the
future anterior of the body axis and then
retracts again toward the ventral side, leaving
notochord tissue behind it.
d) The organizer cells use activated b-catenin as a
master transcriptional regulato...
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- Fall '11