Early Development of Vertebrates Fish Birds and Mammals

Early Development of Vertebrates Fish, Birds, and Mammals

Zebrafish Development

Cleavage in Zebrafish n What kind of cleavage occurs in fish?

Cleavage in Zebrafish n At the time of the mid-blastula transition three cell populations form: ¨ yolk syncytial layer (YSL) ¨ enveloping layer (EVL) ¨ deep cells n What is the importance of each?

Gatrulation in Fish n How does gastrulation begin?

Gastrulation in Fish n What is the germ ring in the developing embryo? n How does hypoblast form?

Gastrulation in Fish n What is the role of convergence and extension?

Axis Formation in Fish n n How has it been demonstrated that the embryonic shield is critical to dorsalventral axis formation? What structures form from it?

Axis Formation in Fish n How does notocord induce neural structures from overlying ectoderm?

Axis Formation in Fish n Where is the Nieuwkoop center and how does it function? What determines the anterior-posterior axis?

Cleavage in Birds n What kind of cleavage occurs in birds?

Cleavage in Birds n What is the area pellucida, area opaca and subgerminal cavity?

Gastrulation in Birds n How is the two-layered blastoderm formed?

Gastrulation in Birds n What is the primitive streak?

Gastrulation in Birds n What is important about the primitive groove? n the primitive knot or Henson’ node? n How does the primitive streak define the embryonic axes?

Gastrulation in Birds n What is the fate of cells migrating through the primitive streak?

Gastrulation in Birds n What happens to the primitive streak?

Gastrulation in Birds n What is needed to complete the process of gastrulation?

Axis Formation in Birds n How does the p. H influence the formation of the dorsal-ventral axis? n How do we know this is true?

Axis Formation in Birds n How goes gravity influence formation of anterior –posterior axis?

Axis Formation in Birds n How does formation of Nieuwkoop center in birds compare with amphibians?

Axis Formation in Birds n From where does the “organizer” in the chick form?

Axis Formation in Birds n How is left-right axis formed? n How has this been demonstrated experimentally?

Early Mammalian Development n What makes mammalian cleavage unique?

Early Mammalian Development n What is compaction and when does it occur?

Early Mammalian Development n How is trophoblast different from inner cell mass? n How does blastocyst form from morula?

Early Mammalian Development n What enables the blastocyst to attach to the uterus?

Gastrulation in Mammals n Development is internal. What modifications to the anatomy does this involve?

Derivation of Mammalian Tissues

Gastrulation in Mammals n gastrulation begins at the posterior end of the embryo What appears to control cell migration and specification?

Gastrulation in Mammals n precursors of ectoderm are anterior to primitive streak n human hypoblast cells are replaced by endoderm precursors

Extraembryonic Membranes

Extraembryonic Membranes n How does placenta provide nutrients and oxygen to fetus?

Anterior-Posterior Axis Formation n Where are the two signaling centers located in the mammalian embryo?

Anterior-Posterior Axis Formation n How is mouse node and AVE similar to chick and frog organizer tissues?

Anterior-Posterior Axis Formation n What kind of interactions occur between visceral endoderm and epiblast in mice?

Anterior-Posterior Axis Formation n What is believed to be the role of the Hox genes?

Anterior-Posterior Axis Formation n What kind of evidence has enabled us to break the Hox gene code? ¨ knockout experiments ¨ experiments with retinoic acid ¨ comparative anatomy studies

Anterior-Posterior Axis Formation n What was shown to occur when the Hoxa 3 gene was “knocked out”? n the Hoxa-2 gene?

Anterior-Posterior Axis Formation n How has the application of retinoic acid provided us information about hox genes?

Anterior-Posterior Axis Formation n What is the connection between hox gene expression and the type of vertebrae formed?

Dorsal-Ventral Axis Formation n What is the connection between a -v pole and d-v axis?

Left-Right Axis n What appears to be responsible for specifying the leftright axis?