Evolutionary developmental studies of cyclostomes and the origin of the vertebrate neck
Version of Record online: 22 APR 2008
© 2008 The Author. Journal compilation © 2008 Japanese Society of Developmental Biologists
Development, Growth & Differentiation
Special Issue: Special ISSUE for the 50th Volume: History and Current Highlights of Developmental Biology
Volume 50, Issue Supplement s1, pages S189–S194, June 2008
How to Cite
Kuratani, S. (2008), Evolutionary developmental studies of cyclostomes and the origin of the vertebrate neck. Development, Growth & Differentiation, 50: S189–S194. doi: 10.1111/j.1440-169X.2008.00985.x
- Issue online: 22 APR 2008
- Version of Record online: 22 APR 2008
- Received 19 November 2007; revised 19 November 2007; accepted 20 November 2007.
- body plan;
- muscle development;
- neural crest
Because they lack some gnathostome-specific traits, cyclostomes have often been regarded as representing an intermediate state linking non-vertebrate chordates and gnathostomes. To understand the evolutionary origins of the jaw and paired fins, lamprey embryos and larvae have been used as comparative models. The lack of the jaw–neck region is a conspicuous feature specific to cyclostomes; however, the absence of these features has been largely neglected both in evolutionary developmental studies and in the field of classical comparative embryology. This review seeks to develop a possible evolutionary scenario of the vertebrate neck muscles by taking the cucullaris (trapezius) muscle as the focus. By combining the comparative embryology of lampreys and gnathostomes, and considering the molecular-level developmental mechanism of skeletal muscle differentiation, this review argues that the establishment of the vertebrate neck deserves to be called an evolutionary novelty based on the remodeling of mesenchymal components between the cranium and the shoulder girdle, which involves both mesodermal and neural crest cell lineages.