Critical Thinking:A sequence is set with a small voxel size, low NEX, and thin slices. What challenge might the image quality present?

Increasing the ETL in a TSE sequence results in:

Developing fly larvae (egg) express Hox genes that work in a similar manner to those in mammals.  Below is a diagram of the larvae Hox gene expression and phenotype.  Choose from the drop down menus to finish the sentence correctly based on the image provided.  3pts “A fly that has loss of function of Hox gene scr, would create a fly that has no [option1], but has an extra set of [option2] in position [option3].”

Spemann used his daughter’s hair to aide in his demonstration that the early newt embryo has an organizing center that is either conditionally or autonomously specified.  (4 pts) Explain how the first division had to occur before he separated the two-cell embryo into two individual cells to demonstrate conditional specification. Explain the molecular signaling that was discovered almost 40 years later to back up Spemann’s experiments that was discussed in class related to frogs.

Predicting results in an embryo (4 pts ) A) predict the phenotype at a specific stage of the organism for each experimental/mutant scenario. B) explain the reasoning that led you to your prediction.   A frog at neurulation that was soaked in a solution with Disheveled dominant negative mRNA since the two-cell stage..

Put the events in the order in which they occurred during development in flies. 1 = first, 5 = last.  (5 pts; 1pt/?)  

Describe events prior to and during fertilization that help lead to establishing the localized signaling pathway that creates an anterior/posterior axis of dorsal mesoderm. You can choose this in any animal that was discussed in this section. (sea urchin, fly, frog, avian, mammal, human). Choose the animal you feel most confident in describing how these events occurred.

Using the time frame of gastrulation and the model organisms bird and mice, explain 2 similarities and 1 difference regarding this process.  Remember in your difference, do not just explain one side and say “and the other one doesn’t”- explain the biology of the difference.

During gastrulation in frogs the bottle cells are the first cells to initiate the inward motion of creating the dorsal lip.  Design an experiment in which you determine if the dorsal lip cells are sufficient for gastrulation.

Another way to compare and contrast in development is to consider what is the equivalent event/structure between organisms.  For the following questions, State the equivalent event/structure between the two organisms listed. 2. Explain the reasoning that brought you to this answer   Axis formation in birds compared to humans