Final answer:
Roxana's in situ hybridization using an RNA probe for Pitx2 aims to visually identify which cells contain Pitx2 mRNA and where the gene is actively expressed in the developing mouse embryo.
Step-by-step explanation:
Roxana is conducting a whole mount in situ hybridization on a 9 day old mouse embryo using an RNA probe for Pitx2. This process allows her to visualize the distribution of Pitx2 mRNA within the cells of the embryo. Since in situ hybridization involves using labeled nucleic acid probes to detect complementary RNA, Roxana hopes to see which cells contain Pitx2 mRNA, indicating where the gene is being actively expressed during embryonic development. This expression pattern can give insights into the roles of Pitx2 in development, such as its involvement in specifying the left-right axis of the body, organ development, and facial symmetry which have been associated with Pitx2 activity.