I´m searching a mod or add-on mod that give me a recessive and dominant genetic. Here´s an example
My grandma sim is a witch , but  her son and daughter aren´t . But her Granddaughter  is. 
You understand? it´s like the magic powers can appear in a random generation. Is exactly the same thing like sims 2 recessive and dominant skin , characteristics... But in a sim-type. 

If you have SP's Population module to allow for Advanced Genetics and the Hybrid mod (only required if one wants actual hybrids, sims born with more than one active occult state), then yes the occult states as well as other attributes can skip a generation. The grandparents have to be in the same world, living or dead, where the baby is born in order for their genetics to be potentially picked up and used.

It's not really the case that the parents, in the middle of the family tree slots in this case, have recessive genes. It's that the mods reach back one more generation when determining the possible outcomes for each baby born. If you took the parents out of the world they came from and into another where the grandparents have no presence, then although the family trees may stay intact (such as by way of the Traveler mod), this cannot happen.