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Hagfish (cyclostomata, vertebrata): Searching for the ancestral developmental plan of vertebrates
Author(s) -
Kuratani Shigeru,
Ota Kinya G.
Publication year - 2008
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.20701
Subject(s) - hagfish , biology , neural crest , synapomorphy , evolutionary biology , vertebrate , monophyly , lineage (genetic) , zoology , anatomy , phylogenetics , embryo , clade , gene , genetics
The phylogenetic position of the hagfish remains enigmatic. In contrast to molecular data that suggest monophyly of the cyclostomes, several morphological features imply a more ancestral state of this animal compared with the lampreys. To resolve this question requires an understanding of the embryology of the hagfish, especially of the neural crest. The early development of the hagfish has long remained a mystery. We collected a shallow‐water‐dwelling hagfish, Eptatretus burgeri , set up an aquarium tank designed to resemble its habitat, and successfully obtained several embryos. By observing the histology and expression of genes known to play fundamental roles in the neural crest, we found that the hagfish crest develops as delaminating migratory cells, as in other vertebrates. We conclude that the delaminating neural crest is a vertebrate synapomorphy that seems to have appeared from the beginning of their evolutionary history, before the splitting away of the hagfish lineage. BioEssays 30:167–172, 2008. © 2008 Wiley Periodicals, Inc.