Differential regulation of avian pelvic girdle development by the limb field ectoderm.

Although limb development has been a subject of intense research over the last decades, development of the girdles has been poorly investigated. Particularly, a detailed analysis of pelvic girdle development including functional data is not available to date. Here, we describe the early steps of the formation of mesenchymal and cartilaginous anlagen of the pelvic elements using alcian blue staining in whole mount embryos and serial histological sections, and the expression pattern of several marker genes to provide an operative basis for further research in pelvis development. Moreover, we describe pelvis development after unilateral hindlimb bud amputation and somatopleural ectoderm extirpation. We show for the first time, that ectodermal signals at pre-limb bud stages are required for pelvis formation. We present evidence suggesting that the regulation of ilium development is different from the development of ischium and pubis.