While the mapping is the same (Or at least very similar), the mesh topology is quite different.

 

Posette is the original "Zygote" woman, sold for $195 without any texture, clothing, morphs or rigging.

Clothed variations were available for the same price, as were morphs for $95 a piece.

Posette and several other Zygote meshes were then licensed for Poser starting with Poser 3.

DAZ then branched off of Zygote to create Poser content while Zygote focused on high end scientific 3D models.

Judy and Don were derived from Posette and Dork to be compatible with the new face room technology.