Analysis of embryonic gene expression patterns in the hagfish

Abstract

Because of its apparently primitive morphology and phylogenetic position, the hagfish is recognized as one of the most basal lineages of vertebrates. In particular, their embryonic gene expression patterns were expected to provide insights into the common ancestral state of the molecular developmental mechanisms. However, it has been difficult to obtain hagfish embryos because this group lives in the deep sea. To overcome this difficulty, a relatively shallow-water hagfish species ( Eptatretus burgeri ) has been used for embryonic gene expression analysis, and successful embryonic in situ hybridization has been reported recently. This protocol explains how to harvest embryos and perform in situ hybridization with embryos of this hagfish species.