Hagfish embryos again: the end of a long drought.
Hagfishes have long held a key place in discussions of early vertebrate evolution. Frustratingly, one basis for such discussions -- namely hagfish embryology -- is very incompletely known, because the embryos of these animals are notoriously difficult to obtain. Fortunately, a recent publication on a Far Eastern hagfish describes a workable procedure for obtaining embryos and then uses this precious material to show that the hagfish neural crest arises by cell delamination as in other vertebrates -- and not by epithelial outpouchings from the wall of the neural tube as previously claimed. Importantly, because hagfish embryos should now be available on a regular basis, the way is open for additional morphological and developmental genetic investigations to help evaluate existing evolutionary scenarios and perhaps suggest new ones.
Holland
Nicholas D
ND
Marine Biology Research Division, SIO, UCSD, La Jolla, CA 92093-0202, USA. nholland@ucsd.edu
D000818:Animals; D005075:Biological Evolution; D017753:Ecosystem; D006196:Hagfishes / Q000196:embryology*; D010802:Phylogeny