Figure 1.

Bone formation in mammals is made possible with a bone inductive protein analogue derived from an invertebrate. In this example, a protein from Drosophila development and an analogue of skeleton building bone morphogenic protein-2/4 (BMP), was injected into the muscle of a mouse, generating new bone. The histological section on the left shows osteoinduction in living mouse subcutaneous tissue following treatment with Drosophila Decapentaplegic (dpp). New bone tissue has been reproduced shown in purple. On the right, for comparison is a histological section of untreated mouse subcutaneous tissue. (Reproduced with permission from PNAS, Sampath et al. 1993 [13]).