Analysis of the genetic and molecular mechanisms of embryogenesis requires effective methods to find and isolate genes that are differentially expressed in normal and altered conditions. Comparative genomic screens can lead to the discovery of known or novel transcripts that change in association with critical events. However, the complexity of cellular responses at the genetic level, as well as functional redundancies in cell signaling pathways themselves, make it difficult to predict how a specific genetic or molecular alteration might translate into a particular developmental phenotype.
