Remember all that talk about unimeshes way back when? Welcome to Genesis.
The concept is quite brilliant in its simplicity. All humanoid characters look pretty much the same when viewing the mesh as a wireframe because they all have a body, arms, legs, hands, feet, neck and head. And probably some other bits I didn’t mention (I’m not human so I tend to forget what you creatures are made of). Anyway, the point is Genesis was born because DAZ realised that underneath all the textures and shapes was a mesh that looked the same when you took the bells and whistles away. So they sat down and created a base which could be turned into any character you want. Male, Female, Child, Gorilla, it’s all the same really. Move a few vertices this way and you get muscles. Move a few vertices that way and you get breasts. And thus the Powerpuff Girls…erm I mean Genesis was born.
Genesis is not a figure. It’s the clay from which all future figures will be made. So V5 for example is just Genesis with its vertices moved around a bit.
This approach works great because as HOF above me said, clothing made for one character will work with any other character build from Genesis. Even UV maps can be swapped out to use a V4 texture on M5. And because it’s one solid mesh creating morphs are also just so much easier. Well to me anyway.