| Date and Time: |
2007-06-04 16:00:00 - 17:00:00 |
| Speaker: |
Ann Campbell Burke
Department of Biology, Wesleyan University |
| Title: |
Evolution in the Vertebrate body plan: Perspective from the lateral plate |
| Summary : | The body plan of vertebrates comprises an axial system of a cranium and segmental vertebrae. In jawed vertebrates the axial system is integrated with an appendicular system, the paired fins or limbs and their girdles. The two systems have become highly integrated during the evolution of diverse vertebrate locomotor adaptations. In a developmental sense however, the body plan is highly conserved throughout the lineage. The appendicular skeletal elements arise from the lateral plate mesoderm (LP) and the axial skeleton arises from the paraxial somites. All of the striated muscles for both systems arise from the somitic myotomes. We have explored the integration of the somitic and lateral plate mesoderm in a variety of tetrapods and define distinct primaxial and abaxial domains in the developing body wall. The dynamic interface between these domains we call the Lateral Somitic Frontier. Certain muscles serve to bridge the axial and appendicular systems, and some of these muscles also bridge the frontier. Experimental evidence from chick and mouse suggests that patterning information changes when somitic cells cross the frontier. I will present a hypothesis whereby primaxial and abaxial domains behave as independently patterned modules facilitating morphological evolution within the vertebrate body plan |
