Whole-mount in situ hybridization to assess advancement of development and embryo morphology

Whole-mount in situ hybridization (WISH) is widely used to visualize the site and dynamics of gene expression during embryonic development. Various methods of probe labeling and hybridization detection are available nowadays. Meanwhile the technique was adapted to be used on many different species and has evolved from a manual to a larger scale and automated procedure. Standardized automated protocols improve the chance to compare different experimental settings reliably. The high resolution of this method is ideally suited for examination of manipulated (e.g., cloned) embryos often displaying subtle changes only. Embedding and sectioning of in situ hybridized specimen further enhance the detailed examination of their gene expression and morphology.