Can bones be controlled without Animation

I am very new to using Unreal for game development. I was wondering if in Unreal would it be possible to import a rigged character with bones and no animation into Unreal and control all the movements of the bones just by using Unreal? For example if I use blender for rigging a hand with bones without animation can I control the movement to of the bones such as making a fist and then change to another hand gesture.
Thanks Alex
Let me know if you need more clarification.

Even though personally I’d rather use the 3D modeling program to make animations and then import them into UE4,
you can now create Animation Assets with Persona within Unreal Engine 4, depending on which version of the engine you’re using.
Note: I haven’t tested with UE 4.10 Preview, but I know you can in UE 4.9

But if I do animations and in the case of my example of using a model of a hand as something I want to control the movements of based on keys that I pressed on my keyboard would I have to go back and create the animation for a new hand gesture that I would like to create?