Whole-mount in situ hybridization (WMISH) is a common technique used for visualizing the location of expressed RNAs in embryos. In this process, synthetically produced RNA probes are first complementarily bound, or "hybridized," to the transcripts of target genes. Immunohistochemistry or fluorescence is then used to detect these RNA hybrids, revealing spatial and temporal patterns of gene expression. Unlike traditional in situ hybridization techniques, which require thin tissue sections whose images will need to be computationally reassembled, the whole-mount technique allows gene expression patterns to be assessed over the entire embryo or structure.

This video will introduce the basic concepts of whole mount staining and detail key procedural steps, including probe design and production, embryo fixation and staining, and post-hybridization signal detection. Viewers will then learn about how developmental biologists are applying WMISH to current research studies.