ABSTRACT
Modern biology is founded on an increasingly sophisticated understanding of genomic mechanisms that specify cellular and tissue anatomy and function during both health and disease. Abnormal gene structure and localization, especially in animals that have been deliberately engineered to have null mutations, are a major cause of embryolethality in developing mice. Therefore, developmental pathologists must be well versed in the in situ molecular pathology methods used to examine anomalous genetic sequences and expression patterns. The main technique utilized for the region-specic assessment of gene distribution in mouse tissues is in situ hybridization (ISH) to reveal mRNA from transcribed genes.3,7,9,12 This procedure may be performed effectively on tissue sections or whole mount (intact) embryos or isolated (intact) organs.
