Question

In Drosophila, loss-of-function Ultrabithorax mutations result in the posterior thoracic segments differentiating into body parts with an identity normally found in the anterior thoracic segments. When the Ultrabithorax gene was cloned, it was shown to encode a transcription factor and to be expressed only in the posterior region of the thorax. Thus, Ultrabithorax acts to specify the identity of the posterior thoracic segments. Similar genes were soon discovered in other animals, including mice and men. You have found that mice possess two closely related genes, Hoxa7 and Hoxb7, which are orthologous to Ultrabithorax. You wish to know whether the two mouse genes act to specify the identity of body segments in mice.

Question 1 -

How will you determine where and when the mouse genes are expressed?

Select the four correct statements.

a. Multiple samples using animals at different stages of development would be needed to assess the temporal pattern of gene expression.

b. Expression of Hoxa7 and Hoxb7 could be studied by PCR to identify tissues containing the genes.

c. Expression of Hoxa7 and Hoxb7 could be studied by translational gene fusions of GFP or lacZ to Hoxa7 and Hoxb.

d. Expression of Hoxa7 and Hoxb7 could be studied by using antibodies to detect the proteins.

e. Multiple samples using animals of different species would be needed to assess the species-specific pattern of gene expression.

f. Expression of Hoxa7 and Hoxb7 could be studied by in situ hybridization to identify tissues containing the mRNAs.

Answer 1

a. Multiple samples using animals at different stages of development would be needed to assess the temporal pattern of gene expression.

c. Expression of Hoxa7 and Hoxb7 could be studied by using antibodies to detect the proteins.

e. Expression of Hoxa7 and Hoxb7 could be studied by in situ hybridization to identify tissues containing the mRNAs.

f. Expression of Hoxa7 and Hoxb7 could be studied by in situ hybridization to identify tissues containing the mRNAs.