Assign material property to cells from gmsh

Hello

I want to generate a mesh in gmsh and assign a material property to each cell. Each cell would have some id. Can this cell id be used inside fenics to define subdomains ?

Alternately can I assign some id to each cell inside fenics and define subdomains based on these id ? The cells may then get deformed but the subdomain should be still defined in terms of the cell id. I cannot use a test on the cell coordinates to decide the subdomain since the deformation can be complicated.

Thanks
praveen