Question 6:  Stained limbs. [6 marks].

Place an Alcian-blue stained chicken embryo under the dissecting microscope. Examine the forelimb (wing) of one of the stained embryos and take a photo.

Label the humerus, radius, ulna, metacarpus, phalanges. (Upload your image)  (5 marks)

On the uploaded image , answer this question:  How many digits (phalanges) does the chicken embryo have on the forelimb?  (1 mark).

Question 14:  Alizarin Red staining.  [4 marks]. 

What does Alizarin Red stain ?  (2 marks)

Question 13: 

Examine the hindlimb of the stained embryos/images and take a photo.

• Label the femur, tibia, fibula, tarsometatarsus, phalanges (digits) . Upload your image.  [5 marks]
• How many digits does the chicken embryo have on the hindlimb?  [1 mark]

Question 12: SOX10 and neural tube electroporation. [16 marks].

SOX10 is an important neural crest gene, normally expressed in neural crest cells in the dorsal part of the neural tube, and remains expressed as they migrate from the neural tube.  

b) Where would you place the DNA construct into the embryo?     (2 marks).

To answer this question, upload a drawn image of where the DNA is placed and where the electrodes would be placed.

c) How does in ovo electroporation work to delivery DNA into cells?  (3 marks).

d) If your hypothesis is that SOX10 can convert neural tube cells into migratory neural crest cells, what result would provide evidence to support this hypothesis ?  (3 marks).

Question 15: Online research 

Do an online search of the literature to answer the two questions below.

a) What is a teratogen?  [2 marks]

b) Name one teratogen that can have an effect on skeleton formation in the embryo (mammal or chicken). What effect does it have? [4 marks]

Question 11:  Vectors for gene delivery. [2 marks].

Which vector should I use to deliver the gene, TOL2 or RCAS virus? (1 mark ) Why?  (1 mark).

Question 10: 

Question 9:  Results interpretation [9 marks]. 

(a) What control was included in the experiment? Was it appropriate?  (3 marks)

b) What conclusions can be made from the collected data? If an embryo is observed with a malformed limb, could there be more than one reason for this?  (3 marks).

c) If this experiment was repeated with the objective of obtaining publication quality results, how could the experiment be improved? Provide THREE suggestions. (3 marks).

Question 8: 

Photograph your embryo and describe the results of your surgery. Enter your results in the class data summary. Your embryo may not have survived. In this case, image one that did (from this either year’s  class or one available from last year.)                 

[ 2 marks]

a) Developmentally, bones can be either endochondral or dermal. 

b) Given one example of each.  (2 marks. 2 mark each.) 

c)  Name one disorder of human endochondral bone development. (1 mark).