Mapping the morphogenetic potential of antler fields through deleting and transplanting subregions of antlerogenic periosteum in sika deer (Cervus nippon).

Morphogenetic fields are a localised and regionally regulated group of cells capable of responding to signals leading to the development of organs. In this study, we sought to determine if antlers develop from such a field. We divided antler fields into four subregions: anterior, posterior, medial and lateral. The antlerogenic periosteum (AP) in each subregion (half of the AP) was deleted and then transplanted into an ectopic site. Antlers form from the cells exclusively residing in the AP, which is located in an antler field. The morphogenetic potential of each subregion was assessed by the antler growth from both the defective field and the transplantation site. The results showed that when the AP anterior half was absent, the fields formed antlers missing the first tine, whereas when the anterior half was present, the ectopic sites regenerated antlers containing the first tine. When the medial half was deleted, the fields could only grow spike antlers, and when the medial half was present, the ectopic sites developed branched antlers. In contrast, the antler fields were able to compensate the defects caused by ablation of the posterior or the lateral half to form relatively normal antlers; and the ectopic sites containing these grafted halves only formed spike antlers. Therefore, antler morphogenetic information was primarily held in the AP anterior-medial halves. This study substantiates the presence of morphogenetic fields in regulating the distinct pattern of antler growth, and demonstrates that antler development is a useful model for the study of morphogenetic fields.